MDL-Error in case of OsmocomBB+OpenBTS

Hi list, I'm trying to connect my OsmocomBB phone to OpenBTS and I always got MDL-Error in mobile app log when MS trying to perform LU. Part of log (full mobile log in attach): <0001> gsm48_rr.c:355 new state connection pending -> dedicated <0005> gsm48_mm.c:3911 (ms 1) Received 'RR_EST_CNF' from RR in state wait for RR connection (location updating) (sapi 0) <0005> gsm48_mm.c:404 starting T3210 (loc. upd. timeout) with 20.0 seconds <0005> gsm48_mm.c:924 new state wait for RR connection (location updating) -> location updating initiated <0001> gsm48_rr.c:4984 MDL-Error (cause 3) ignoring <0001> gsm48_rr.c:4987 MDL-Error (cause 3) aborting <0001> gsm48_rr.c:355 new state dedicated -> idle In wireshark trace (from OpenBTS, attached) I see that MS sends LURequest (packet 359) and BTS responds with LUAccept (packet 440) but MS never receive this message because of error. As I understand this is "unsolicited UA response" from 08.58 (9.3.22) but I do not know how to fix that or properly debug. I'm using latest sylvain/testing and official OpenBTS 2.8. "Usual" (not with OsmocomBB) phones works with OpenBTS fine and OsmocomBB phones works fine with "usual" (not OpenBTS) networks. Thanks, Pavel