I think the lag might be due to one of the following:
1. BLE connection interval being too high
2. Over the air interference
3. Delay loops in firmware
Can you check these and if possible attach a sniffer log (if you have one).
Undesh, thanks for the feedback.
Regarding BLE connection interval.
Do you or anyone else have optimal settings for real time communication (best practices)?
Almost all hope was gone, but we came to a solution finally....
It was indeed the timings in the BLE properties tab that solved the issue. And I can say it is a 'Day and Night' difference!!
Fast advertising min and max from 20ms to 100ms...
Show advertising timeout from 150 to 120 ms
Slave latency from 25 to 20 ms
Connection supervision from 2000 to 30000 ms