SetTimerSV and SetCtrSV writes to the EEPROM, and during the EEPROM read/write the CPU needs to turn off its interrupts in order to prevent corruption to the read/write data. This could however lead to temporary disruption to communication with a HMI if the write happens midway when receiving a MODBUS command as a byte of character may be lost especially at high communication speed.
You could reduce the communication error occurrence by using the SETTIMERSV and SETCTRSV sparingly. E.g. if you are to make changes to timers or counter set values using some up/down keys, then you should make the changes in DM first which are stored in RAM, and only when the changes have been finalized then write them to the EEPROM via SETTIMERSV and SETCTRSV commands by triggering a "Record" or "Enter" relay.