CAN bus TX failing in a strange way
In your first image you expect TX to transmit messages from the other bus. But it does not even try, which may suggest the buffer for incoming messages is empty or the controller already went error passive. What you can see is high bus utility due to the minimum time between frames.
Yet they are acknowledged correctly.

In your second image you are looking at an error flag at the end of the frame. This might suggest CRC failure. Please check the error counters. 

It's a good thing CAN bus controllers have sophisticated error counters. So you can go an look which error occurred by looking the status registers.  

Please check:
  CAN transmit status register (CAN_TSR)
  CAN error status register (CAN_ESR)  

It's also more valuable to look at the CAN bus with more then only an oscilloscope. See if you can acquire at least a logic analyzer (with protocol decoding). Or an analyzer from Kvaser/Vector/Peak.