[BUG] b2b: CANCEL not processed

[ovidiusas]

OpenSIPS version you are running

version: opensips 4.1.0-dev (x86_64/linux)
flags: STATS: On, DISABLE_NAGLE, USE_MCAST, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, HP_MALLOC, F_PARALLEL_MALLOC, DBG_MALLOC, CC_O0, FAST_LOCK-ADAPTIVE_WAIT
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535
poll method support: poll, epoll, sigio_rt, select.
git revision: eb4fba7af
main.c compiled on 02:02:10 Apr 26 2026 with cc 14

Describe the bug
CANCEL is being ignored by b2b.

To Reproduce
Make a call and cancel it.

Relevant System Logs
3.6 logs (CANCEL works as expected):

INFO:b2b_entities:b2b_prescript_f: start - method = CANCEL
INFO:b2b_entities:b2bl_search_iteratively: Search for record with callid= 8212ac60-37f7fcf7-ac957d7a@192.168.4.118, tag= 6FF32DB4-83D4425B
INFO:b2b_entities:b2bl_search_iteratively: Found callid= 8212ac60-37f7fcf7-ac957d7a@192.168.4.118, tag= 6FF32DB4-83D4425B
INFO:b2b_logic:b2bl_parse_key: hash_index = [480]  - local_index= [0]
INFO:b2b_logic:b2b_logic_notify: b2b_entities notification cb for [480.0] with entity [bk2bk.230.496.1777183120.908584362]
INFO:b2b_logic:b2bl_search_entity: Key [bk2bk.230.496.1777183120.908584362]
INFO:b2b_logic:b2b_logic_notify_request: b2b_entity key = bk2bk.230.496.1777183120.908584362
INFO:b2b_logic:b2b_logic_notify_request: request received for tuple[0x73019cc7b5b8]->[480.0]
INFO:b2b_logic:_b2b_pass_request: Send request [CANCEL] to peer [bk2bk.480.3067745.1777183120.450820202]
INFO:b2b_entities:b2b_parse_key: hash_index = [480]  - local_index= [3067745]
INFO:b2b_entities:b2b_search_htable_next_dlg: entering with start=(nil), table=0x73019cba4e70, hash=480, label=3067745
INFO:b2b_entities:b2b_search_htable_next_dlg: searching  callid 38[bk2bk.480.3067745.1777183120.450820202]
INFO:b2b_entities:b2b_search_htable_next_dlg: searching   totag 32[a9b3189219ab534f4e3559e91b7fcf5b]
INFO:b2b_entities:b2b_search_htable_next_dlg: searching fromtag 36[d80c8783-8418-49de-93d1-c20ae0189e06]
INFO:b2b_entities:_b2b_send_request: Send request [CANCEL] for entity type [1] for dlg[0x73019cc8b680]->[bk2bk.480.3067745.1777183120.450820202]
INFO:b2b_entities:_b2b_send_request: send cancel request
INFO:b2b_logic:entity_event_trigger: Triggerd event [3] for entity [bk2bk.480.3067745.1777183120.450820202]
INFO:b2b_logic:b2bl_parse_key: hash_index = [480]  - local_index= [0]

master logs (CANCEL is ignored):

INFO:b2b_entities:b2b_prescript_f: start - method = CANCEL
INFO:b2b_entities:b2bl_search_iteratively: Search for record with callid= c430ace4-90fcfb4b-f37d63de@192.168.4.118, tag= C23F9FF8-6A41D6F
INFO:b2b_entities:b2bl_search_iteratively: Found callid= c430ace4-90fcfb4b-f37d63de@192.168.4.118, tag= C23F9FF8-6A41D6F
INFO:b2b_logic:b2bl_parse_key: hash_index = [480]  - local_index= [0]
INFO:b2b_logic:b2b_logic_notify: b2b_entities notification cb for [480.0] with entity [H]
INFO:b2b_logic:b2bl_search_entity: Key [bk2bk.93.497.1777183504.1811009363]
ERROR:b2b_logic:b2b_logic_notify_request: No b2b_key match found [H], src=0
INFO:b2b_logic:entity_event_trigger: Triggerd event [3] for entity [bk2bk.93.497.1777183504.1811009363]
INFO:b2b_logic:b2bl_parse_key: hash_index = [480]  - local_index= [0]

See the bogus entity: H instead of bk2bk.93.497.1777183504.1811009363