yes it can be related. Please upload the project source files so I can inspect details of timing, Modbus baudrate etc.
Try the following and observe if the problem persists:
- Read only 1 register, no writing. Delete all the other items from Modbus configuration.
- Read 2 registers, no writing.
- Read 4 registers, no writing.
- Read 4 registers, write 1 register.
Let me know.