Midi synced drum machine getting out of time after 1 loop

I have a 100 bpm beat from Logic playing. I have the project Midi synced and sending clock information out. During the first run through, the external drum machine (a TR-8) and Logic are perfectly in sync. Once the loop restarts, everything is off. -- I think the drum machine is somehow skipping ahead, because the drum hits that used to land on say the 1 and the 3 and are now hitting 1/16th after...

If I don't loop and just copy and paste the drum beat for a long long time, the external drum machine and the logic beat stay in sync. it's the loop that is causing the problem..

Any suggestions? -- Thanks in advance!