@Wayne-Workman I know in the inits that the developers added the loop for the count of 4 for dhcp discovery, which I think the timing should have put it past the 27 seconds forwarding threshold. There should be two values. There should be a loop count and then a wait time you can play with. You “could” pass a kernel parameter to adjust either. It wouldn’t be that hard to extract the inits and update the code. This way if the kernel new parameter didn’t exist then the defaults would be used.
Just in case its not a spanning tree issue we have also seen issues with certain network adapters and green ethernet (802.1az). Typically a dumb (unmanaged) switch would mask this issue. But in the OPs case they are using a pretty old dell o745, and it doesn’t have any of the green ethernet stuff.