Best debugging trick ever:

Wear your fucking glasses while coding so that you do not mistake COMMA(,) with a DOT (.).

So by
1. Doing that (which obviously aren't a huge number) and
2. Cleaning my screen (yes that).

I was able to wrap my head around the issue that almost wasted one day.
So what I intended to pass as string concatenation join operation value actually was being passed as an argument to the underlying function (that wasn't taking care of it and returning a timestamp from thin air).

Murphy's Law in production and practice.
Nice!

Depressing music continues......!