Not sure if this is your issue but there is an old DVD issue where OR operand works in windows client but not in web client. If you are using OR operand, please change it to |.

| will work in both windows and web clients.

Thanks for your reply Jason, But this is already verified, we are using operand '|' and not 'OR' !!

One more thing I want to add here is... Initially, everything was fine from last 4 years. The issue started coming recently. The old formats where we have similar visibility conditions are working fine. Only new developments are giving this type of issues..

Something must be different. Strange that old formats works but not new formats. To confirm, paste exact old visibility condition from old format into new format and see if it works. That will confirm if it's specific to the condition or not.
Also, try debugging the condition. e.g condition = ($A && $B) || $C. Remove each variable onet by one and retest to confirm which variable is the root cause. test condition = ($A && $B), test condition = $A, test condition = $B, test condition = $C. 

I also encountered 2 similar issues with a customer. See https://kmviewer.saas.microfocus.com/#/OCTCR19X1117220 and https://kmviewer.saas.microfocus.com/#/OCTCR19X1936439.

My customer was using multiselect.selection function to create a variable in a condition. This variable resulted in a NULL value. Windows client is smarter, if the variable is NULL, it does not perform the condition. Web client will try to perform the condition even if the variable is NULL which results in error condition. So, check if any of your variables are returning NULL value. You can add the variable into the format to check on it's value. Web client do not handle NULL value properly and this defect will most likely be fixed in versions newer than 9.72

Hi Jason, Thanks for your suggestion. I will check this and come back.