Hi Ahmad,
Thanks for your reply, but unfortunately your solution is not correct.
I have tried the following and none of it seems to fix the issue.
– Purge everything from wp, browser. Does not work
– Tried on brand new PC which had no previous cache.
– Uninstalled chrome and installed again and tested.
– Freshly installed and Tested on Mozilla and Edge.
Each time behaviour is same with FOUC visible. I doubt it is due to cache.