Have any of you experienced the following problem:

We have a sector plugged into a Mikrotik router. We noticed our PPPOE sessions started to fail authentication on the Mikrotik log. We found that we could no longer ping any of the SM's from the router, however we could still access the sector and ping the registered SM's from the AP. So basically we could ping the AP, login to the AP, ping devices from the AP (ePMP1000 connectorised). But we could not ping devices from the Mikrotik. All units are on the same IP range, After much troubleshooting we found that one of the connected SM's was causing this anomaly. Once we mac rejected the unit, the other 15 SM's started working as before. We could now ping them from the Mikrotik and it was business as usual.

Has anyone else experienced this, or know why that would happen?

Many Thanks

Sounds like the issue we used to have with our UBNT SM's, it would happen during lightning storms and power outages.  Then we started requiring proper grounding for our customer Cat-5 and surge protectors.  We have yet to see the issue on the Force 200 (knocking on wood).