Data Connection during calls

For clarity.. call made or received using primary sim and data connection gets suspended for secondary Sim during call..
Weird thing noticed is, if auto switch data is enabled data for primary sim gets activated during call..

This is an LTE issue, not a bug. Samsung has released a workaround on some phones as in the screenshot. Until it hits your phone, I suggest you switch your secondary (non-data) SIM to 2G Only mode. This will stop the data switching. On the downside, call quality will drop, but on the upside, your signal strength will improve because operators have near perfect 2G coverage everywhere.

Note, this will not work with Jio, as Jio does not have 2G. Only Airtel / Vi / BSNL do.

No. It is a bug.
If my data is set to secondary sim and I make a call using my primary sim then it tries to switch data to primary sim, which is wrong. If I simply disable data switching then when I use primary sim for call data on secondary sim gets suspended.