OTV Mac flush issue

Rick Wood

We have otv running between 2 DC’s.

2 otv routers in each DC.

I have noticed that the the mac table (show otv route) on one of the otv routers is being refreshed/reset every 15 mins.
How can this be resolved.
I have looked at the bridge-domain mac aging timer which can be set to 3600secs. But it is unclear whether this needs to be configured under every BD -x(vlan).
Any assistance or guidance would be greatly appreciated.