BGP Prepend issue


We have 2 DC’s and same ISP at both the DC’s. Also, we have our old public pool and advertised in both the DC’s and configured Prepend.
Its working fine from last 5 to 6 months and suddenly we observed that from a few locations the trace is going to 2nd DC which is causing an issue for us.

Could anyone suggest to fix the issue.

Hello, @san!
It will be hard to say something without configuration from both routers. Can you provide them?