Hi Nikospps,
I'm not certain. Are you getting any events or log messages?
If I had to guess, there is an illegal address exception in your logs, and the actual modbus requests span your existing point and your new point, but in between in those addresses is one the device doesn't grant permission to read.
So, to fix, use the "Contiguous batches only" setting, or decrease your maximum register / bit request size until it stops happening.