TC SM unit test sometimes fails

This unit test fails on average 36/10000 times on the following error:

Unit_test_TC_SM ..................Subprocess aborted***Exception: 0.13 sec
test_tc_sm: /flexric/src/sm/tc_sm/enc/tc_enc_plain.c:2274: tc_enc_ctrl_msg_plain: Assertion `it == ba.buf + ba.len' failed.

Example CI run: https://jenkins-oai.eurecom.fr/job/OAI-FLEXRIC/162/