Not sure a bug. that about 'max_sp_recursion_depth'

It is few days ago's issue from now.

1. There is a SP which contain long(several hundreds lines)
2. set max_sp_recursion_depth = 1 by config.ini.
3. Call recursively(mannually or event automatically. seem doesn't matter).
4. You can see max_sp_recursion_depth limit error message.
4. DB freak out.
> freak out means... seem some internal thread stack broken(that memory overrun).
> DB system totally freak out.

Have no idea it reproducible with just a simple SP by your side,
but from my side it easily happens. The SP fully use memory temp table by hint SQL_SMALL_RESULT' and multiple CTEs.