ERROR: too many dynamic shared memory segments

Hello,
We are running postgres 11.5 and in the last two weeks we did :

- upgrade of postgres to 11.5 from 11.4
- increased shared_buffer to 1/3 of the memory
- increased effective_cache_size = 160GB from 120
- increased checkpoint_completion_target = 0.9 from 0.7
- increased checkpoint_timeout = 1h
- increased work_mem = 2GB (this can be set up to 4GB) from 600MB

Since that, in the last two weeks we saw an increment of this error :

ERROR: too many dynamic shared memory segments

Is there any relation between these parameters or the pgsql 11.5 version?

Any help can be appreciated.

Thank you,
Nicola