Hi Edwin,
Shoot, sorry for the trouble!
The widget dates are something we found to be an issue with several other customers. The good news is that we released a patch for it just the other day. Have you installed The Events Calendar 3.12.5 and Events Calendar PRO 3.12.6? Those two should clear the issue, but please do let me know if that is not the case.
Also, it could just be that some time has past since you created this thread, but it looks like the dates are currently correct (screenshot). Hopefully you were able to resolve it, but let’s at least make sure we’re using the most current versions and go from there. 🙂
Thanks!
Geoff