Although the political leadership of Chairman Yasser Arafat's Palestine Liberation Organization appears to have recovered from the jolt of evacuation from their capital in exile of West Beirut last summer, indications are that many of the organization's once-proud fighters have not fared so well.

While it is not a subject PLO leaders will disuss readily, there is deep concern within the organization about the morale of many of the guerrillas who last summer withstood for 2 1/2 months the Israeli Army's punishing siege of the Lebanese capital.

Dispersed to isolated camps in eight different Arab states -- disarmed of their once-ubiquitous AK47 sidearms and kept under often rigid control by their host governments -- PLO units have been swept by what some senior PLO officials admit privately is severe "demoralization."

While travel restrictions to most of the isolated camps make on-scene verification of the problems difficult, reliable reports here and in Tunisia, Arafat's new personal headquarters, indicate that there have been angry protests by fighters in the camps, insubordination to officers and, in at least one instance, mass desertions.

The camp where there is the most solid evidence of trouble is at Oued Zarga, Tunisia, 50 miles west of Arafat's new offices in the weathered, beachfront Hotel Salwa, south of the Tunisian capital of Tunis.

According to information provided by senior Tunisian officials, shortly after about 850 PLO fighters were moved in September to Oued Zarga, a former agricultural college in a lonely and barren corner of the lower Atlas Mountains, there was a riot among the fighters that had to be put down by force by guerrillas from Arafat's Fatah organization.

The exact reasons for the outburst are unclear. Senior PLO officials, who say only that there has been "tension" at the camp, maintain that it was a reaction to the Christian massacre of Palestinian civilians at Beirut's Shatila and Sabra refugee camps, where many fighters still had their families.

Official Tunisian sources, however, indicate that the riot occurred before the massacre and was either a revolt against conditions in the camp or a protest against the PLO policies that brought them there.

The revolt ringleaders apparently had their heads shaved and were locked up in makeshift jails in the agricultural college building, according to one reliable Tunisian source. The tension, however, did not go away. Although Tunisian Army units defended the periphery of the camp, hundreds of demoralized fighters simply slipped through the thin barbed-wire enclosures under the cover of darkness and deserted.

Tunisian officials believe many, perhaps 200, made their way westward by night to escape across the border into Algeria. Others apparently found their way into Tunis, where, according to foreign diplomats, those who had legal passports or refugee papers began turning up asking for visas to leave Tunisia.

The camp was immediately placed off-limits to all outsiders. Strangers caught driving by the camp and peering through the olive groves that shields the new Quonset huts that have replaced its original tents, are routinely flagged down by patrolling Tunisian police, who demand identification and often interrogate the onlookers.

PLO officials at the Hotel Salwa bluntly reject all requests to visit the camp.

A Tunisian Cabinet minister, however, said that the camp's population has dwindled to but "a few hundred" in the past two months.

Confronted with this information, PLO officials admitted that some fighters left the camp, but they maintained that these were only part-time fighters who had been given authorization to return to regular jobs in other parts of the Arab world.

Published reports that Israeli intelligence suspects that the disappearing PLO fighters in Tunisia are surreptitiously making their way back to Syria or Lebanon's Bekaa Valley are not given much credence by foreign diplomats here. They confirm PLO complaints that the Syrians have kept all PLO movements across their borders under tight control. The Syrian government, according to diplomats, also has refused all PLO suggestions that more of their former fighters from Beirut be allowed to settle in Syria.

PLO officials say that if they could, they would like to regroup their fighting forces in Syria and Jordan, on the edges of the Israeli-occupied territories they remain determined to return to someday. But they say that so far they have received no permission to do so, either from Syrian President Hafez Assad or Jordan's King Hussein.

In the meantime, there have been further reports of dissatisfaction and protests from other PLO camps in Sudan, Iraq, Algeria and South Yemen.

"Of course there are difficulties in these new places our fighters have gone," said Khalil Wazir, the PLO's senior military chieftain, who is also known as Abu Jihad. "Every Palestinian wants to be near his own people, near the occupied territories."

"If you were used to living in Lebanon, how do you think you would feel to find yourself suddenly living in Aden?" he asked, referring to the capital of South Yemen.

Because the biggest complaint from the fighters has been the often primitive living quarters they have been assigned, Wazir said, the PLO has sought to raise morale by improving the camps with new water wells, electricity generators and, where possible, prefabricated housing.

"We hoped originally that we would only be in these distant camps temporarily," Wazir said. "But now we are having to establish more permanent bases because we don't know how long we will have to stay there."