can you perform some Abis traces on the RSL’s of different cells ? you should be able to find where are the differences.
i could list down some possibilities, but i can’t know if one of them is correct :
1) GPRS paging is done per RAC, on the PCH. So cells from same LAC but different RAC will have different paging requests.
2) due to the Gs interface (SGSN – MSC), the CS paging go through the SGSN, which can point the paging onto one specific cell only, if the MS is in GMM READY MODE.
3) CS paging repetition on only some cells (due to RSL congestion, or PCH congestion, maybe it leads to retransmission of the paging ?)
4) some software failures ?
5) different paging types (IMSI or TMSI paging) depending on the cell.. (???? sounds impossible.. !!!)