I've posted about a somewhat related issue
viewtopic.php?f=2&t=177480&p=872068#p872068.
I get carrier aggregation (Primary: B1, CA: B20, optimally) just fine. But every once in a while it swaps them around for 5 minutes or so which absolutely tanks performance. If I use cell lock to lock the Primary Band to the right EARFCN I lose Carrier Aggregation. The Primary Band stays B1 on the specified tower and B20 never gets picked up as the CA Band...
Maybe cell lock only supports intra-band CA? The examples on the wiki are B3@5Mhz + B3@20Mhz, with the Primary channel locked.