v1.2.3 MTU changes from 1700 to ­~670

Hi,
a v1.2.3. station and ap are connected.

From time to time we lose connectivity to the STATION (reboot helps for a short while).

STA responds via Management in vlan the same way as the Data vlan.
During these time-outs no packets were lost on 32 bytes.

This is really critical as we cannot use the link at all.

After reboot the STA will respond with 1472, if we try to send customer data or access the management it goes back to about ­~670MTU. :[

[admin@agnis_maja] | ping address=94.101.232.229 do-not-fragment size=669
HOST SIZE TTL TIME STATUS
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 timeout
sent=5 received=0 packet-loss=100%

[admin@agnis_maja] | ping address=94.101.232.229 do-not-fragment size=668
HOST SIZE TTL TIME STATUS
94.101.232.229 668 64 49ms
94.101.232.229 timeout
94.101.232.229 668 64 48ms
94.101.232.229 668 64 16ms
94.101.232.229 668 64 16ms
sent=5 received=4 packet-loss=20% min-rtt=16ms avg-rtt=32ms max-rtt=49ms

[admin@agnis_maja] | ping address=94.101.232.229 do-not-fragment size=667
HOST SIZE TTL TIME STATUS
94.101.232.229 667 64 49ms
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 667 64 19ms
94.101.232.229 667 64 16ms
94.101.232.229 667 64 46ms
94.101.232.229 667 64 16ms
sent=7 received=5 packet-loss=28% min-rtt=16ms avg-rtt=29ms max-rtt=49ms

[admin@agnis_maja] | ping address=94.101.232.229 do-not-fragment size=666
HOST SIZE TTL TIME STATUS
94.101.232.229 666 64 79ms
94.101.232.229 666 64 46ms
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 timeout
94.101.232.229 666 64 20ms
sent=6 received=3 packet-loss=50% min-rtt=20ms avg-rtt=48ms max-rtt=79ms

admin@agnis_maja] | ping address=94.101.232.229 do-not-fragment size=665
HOST SIZE TTL TIME STATUS
94.101.232.229 665 64 46ms
94.101.232.229 665 64 16ms
94.101.232.229 665 64 16ms
94.101.232.229 665 64 16ms
94.101.232.229 665 64 19ms
sent=5 received=5 packet-loss=0% min-rtt=16ms avg-rtt=22ms max-rtt=46ms

the same with version 1.3.4

Janis - Without understanding your network’s configuration, we may not be able to assist you correctly. We would like to troubleshoot this for you. Please contact Cambium by mailing support@cambiumnetworks.com or calling the Support phone number (http://www.cambiumnetworks.com/support/contact-support)

Hi,
ok, thanks.
I’ll write an email to support with diagrams and everything.