MACFLAP on two trunks - No loops, not sure what's going on. HELP!

[CPynch]

Here's the basic layout. 

Both cisco switches are flapping on ports 23 and 25 which are trunks. The MAC's exist on the 'right' side only. No router on the network, layer 2 only. 

Am I missing something simple? 

[CPynch]

This was it. I adjusted the priority manually, and the flapping stopped! Not sure how that changed, or why... bu that was absolutely the fix. Thanks,  @MHM Cisco World!

[MHM Cisco World]

You are so so welcome