How has UNRWA the UN organization responsible for Palestinian refugees contributed to the perpetuation of the conflict ?

No and it does not give Palestinian refugees advantage over other refugees, in the matter of facts it is the opposite. Let’s delve right into it:
Palestinian refugees are distinctive in that they receive services from a particular UN body, the Relief and Works Agency (UNRWA), rather than the UN High Commissioner for Refugees (UNHCR). According to critics, this set-up gives the Palestinians an unfair advantage by singling them out for special attention.
The Trump administration even defunded UNRWA in 2018 on the grounds that its work “perpetuates” the Palestinian refugee crisis. Citing similar grounds, Israeli Prime Minister Benjamin Netanyahu tweeted in 2017 that the agency should be disbanded and merged into UNHCR. Anti-Palestinian voices have continually alleged that UNRWA’s mandate unjustly advantages the Palestinians in comparison to all other refugees.
In fact, the opposite is true. While UNRWA is distinct from UNHCR, the differences actually disadvantage Palestinian refugees. UNRWA has a much narrower mandate than UNHCR, with no allowance for protection activities. The result is a “protection gap,” whereby Palestinians are the only refugees in the world unprotected by an international body.
Palestinian children and teachers hold placards during a protest against the reduction of educational programs given by UNRWA at the Rafah refugee camp in the southern Gaza Strip, Aug. 15, 2015. (Abed Rahim Khatib/Flash90)
What’s more, UNRWA’s mandate is limited to service provision, while UNHCR is mandated to pursue solutions to refugee crises — and the UNHCR’s preferred solution is, in fact, refugee return. Were Netanyahu to get his wish and see the Palestinian refugees subsumed under UNHCR’s mandate, he might get more than he bargained for.