Last week, Microsoft released an on-demand hotfix for SQL Server 2014, which you shgould consider installing if you are using Availability Groups and any of the relevant databases use CLR user-defined types (UDTs). The symptom is described in KB #3042370, and you should get enough info just from the title to convince you to apply it:
The actual hotfix has to be downloaded from a different KB article, KB #3043788. The hotfix will bring SQL Server to version 12.0.2485. As always, please regression test any updates before applying them in production.
For more broad advice about hotfixes and cumulative updates for SQL Server 2014, see this blog post.