Just found a KB with the answer:
https://kb.juniper.net/InfoCenter/index?page=content&id=KB32060&cat=&actp=LIST
Summary: This article explains the meaning, cause and solution for the syslog message: BRCM_COS_HALP(brcm_cos_ng_access_bind_scheduler_map_ifd:2694): Transmit rate configured 7500 is less than minimum supported 8000, wont be honored This message does not impact traffic. It is fixed in Junos 15.1X53-D56. Cause: If any interface is configured with 10Mbps speed on the switch, this log message is expected. It is triggered by speed configuration change, link down/up or traffic changes. It also occurs If any interface negotiates with a partner that has 10M speed configured.