eModbus: E2 - CRC check error

Describe the bug: When trying to read holding registers I get a E2 - CRC check error relatively often. When enabling #define LOG_LEVEL LOG_LEVEL_DEBUG there are no E2 - CRC check error anymore.

Modbus Blocks:

Block:	Min:	Max:	Size:
000	000	030	031
001	041	057	017

Expected behavior: There shouldn’t be any E2 - CRC check error.

Ouput (LOG_LEVEL_DEBUG):

[D] Sent packet: @3FFB264C/6:
  | 0000: 01 03 00 00 00 1F                                 |......          |
[D] 200229| ModbusClientRTU.cpp  [ 198] handleConnection: Request sent.
[D] Raw buffer received: @3FFB2A6C/67:
  | 0000: 01 03 3E 00 60 00 00 00  00 00 00 00 00 00 00 02  |..>.`...........|
  | 0010: 79 00 D6 00 6D 00 01 00  00 01 C8 00 01 00 02 00  |y...m...........|
  | 0020: E2 00 00 02 B9 00 00 0B  D6 27 28 02 79 4C 9F 00  |.........'(.yL..|
  | 0030: 00 00 08 00 50 0F 71 0C  A8 00 01 00 01 00 64 00  |....P.q.......d.|
  | 0040: 01 55 5C                                          |.U\             |
[D] Received packet: @3FFB2CCC/65:
  | 0000: 01 03 3E 00 60 00 00 00  00 00 00 00 00 00 00 02  |..>.`...........|
  | 0010: 79 00 D6 00 6D 00 01 00  00 01 C8 00 01 00 02 00  |y...m...........|
  | 0020: E2 00 00 02 B9 00 00 0B  D6 27 28 02 79 4C 9F 00  |.........'(.yL..|
  | 0030: 00 00 08 00 50 0F 71 0C  A8 00 01 00 01 00 64 00  |....P.q.......d.|
  | 0040: 01                                                |.               |
[D] 200356| ModbusClientRTU.cpp  [ 204] handleConnection: Data response (65 bytes) received.
[D] 200364| ModbusClientRTU.cpp  [ 225] handleConnection: Response generated.
[D] 200371| ModbusClientRTU.cpp  [ 193] handleConnection: Pulled request from queue
[D] Sent packet: @3FFB2604/6:
  | 0000: 01 03 00 29 00 11                                 |...)..          |
[D] 200391| ModbusClientRTU.cpp  [ 198] handleConnection: Request sent.
[D] Raw buffer received: @3FFB2A6C/39:
  | 0000: 01 03 22 00 00 00 00 00  00 00 00 00 00 00 00 00  |..".............|
  | 0010: 00 00 00 EB 34 00 00 55  14 00 00 96 5C 00 53 C5  |....4..U....\.S.|
  | 0020: B8 00 16 06 DA 3F C9                              |.....?.         |
[D] Received packet: @3FFB2604/37:
  | 0000: 01 03 22 00 00 00 00 00  00 00 00 00 00 00 00 00  |..".............|
  | 0010: 00 00 00 EB 34 00 00 55  14 00 00 96 5C 00 53 C5  |....4..U....\.S.|
  | 0020: B8 00 16 06 DA                                    |.....           |
[D] 200475| ModbusClientRTU.cpp  [ 204] handleConnection: Data response (37 bytes) received.
[D] 200483| ModbusClientRTU.cpp  [ 225] handleConnection: Response generated.
[D] 201190| ModbusClientRTU.cpp  [ 126] addRequestM: request for 01/03
[D] 201191| ModbusClientRTU.cpp  [ 175] addToQueue: RC=01
[D] 201191| ModbusClientRTU.cpp  [ 137] addRequestM: RC=00
[D] 201191| ModbusClientRTU.cpp  [ 193] handleConnection: Pulled request from queue
[D] 201196| ModbusClientRTU.cpp  [ 126] addRequestM: request for 01/03
[D] 201209| ModbusClientRTU.cpp  [ 175] addToQueue: RC=01
[D] 201214| ModbusClientRTU.cpp  [ 137] addRequestM: RC=00

Handle RTS method:

void handle_rts(bool toggle_level) {
  if (!w5500_initalized) {
    digitalWrite(RTS_PIN, toggle_level);
  }
}

Additional info:

I already tried to add the crc to my messages beforehand via. addCRC(), the problem seesm to lie in the response tough so that didn’t solve any issues. Additionaly it seems that playing around with delays didn’t really help as well, because E2 - CRC check error are less frequent but they still appear seemingly randomly.

I have also tried to play around with the Modbus interval timeout, but it also didn’t really help in solving the issue. I also seem to get a response everytime so the request itself seems to be fine and it seems to be received on the other side as well.

---

Is there something I am missing with the CRC16 check or do I need to add something like a delay() etc? Because I really can’t fathom what exactly the problem could be.