"nocanc mqtt" stops processing messages (version 0.3.3)

[mjbmikeb2]

After a few minutes the nocand -> "nocanc mqtt" ack mechanism stops working reliably and eventually it also stops processing outbound MQTT messages.
I can tell that the data is getting through to the canzero because I programmed the canzero to send a "_received a message" debug message every time a message arrives.

[[mqtt.subscribers]]
channel="node20_c_enable_light"
topic="node20/c_enable_light"

Output from nocand
2021/02/16 13:50:33 DEBUG++ Broadcasting channel update on node20_c_enable_light: "node20/c_enable_light=1"
2021/02/16 13:50:33 DEBUG++ SEND FRAME EXT@9000001e 8: 6e 6f 64 65 32 30 2f 63>
2021/02/16 13:50:33 DEBUG++ SEND FRAME EXT@8000001e 8: 5f 65 6e 61 62 6c 65 5f>
2021/02/16 13:50:33 DEBUG++ SEND FRAME EXT@8010001e 7: 6c 69 67 68 74 3d 31>
2021/02/16 13:50:33 DEBUG ** Received **
2021/02/16 13:50:33 INFO Updated content of channel 'node20_debug' (id=0) to "_received a message"

However the output from "nocanc mqtt" says there is a problem
2021/02/16 13:50:33 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': MsgId mismatch is reponse to request channel-update-event (request MsgId: 2, response MsgId: 3)

Once it prints the first warning it repeats for every susequent subscription message and may also stop the processing of outbound MQTT messages. Sometimes it recovers, sometimes it doesn't.

For example:
2021/02/16 14:40:27 INFO Published 5 bytes from channel '196_s_p_motor_speed' to topic '196_s_p_motor_speed'
2021/02/16 14:40:27 INFO Published 3 bytes from channel '13b_s_p_flow_count' to topic '13b_s_p_flow_count'
2021/02/16 14:40:27 INFO Published 5 bytes from channel '108_s_p_pool_top_temperature' to topic '108_s_p_pool_top_temperature'
2021/02/16 14:40:27 INFO Published 5 bytes from channel '109_s_p_pool_bottom_temperature' to topic '109_s_p_pool_bottom_temperature'
2021/02/16 14:40:27 INFO Published 2 bytes from channel 's_calculated_led_strip_brightness' to topic 's_calculated_led_strip_brightness'
2021/02/16 14:40:28 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:29 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:30 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:31 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:32 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:33 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:34 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:35 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:36 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:37 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:38 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe
2021/02/16 14:40:39 WARNING Failed to send 23 byte message for NoCAN channel 'node20_c_enable_light': Failed to write 61 bytes for value of encoded event 9, write tcp 127.0.0.1:60888->127.0.0.1:4242: write: broken pipe

When it looks like this there is no recovery.

The setup is one canzero sending approx 25 messages per second and receiving 1 message per second.