Hey @epsragh,
Would it be possible to see the output from dmesg | grep i2c? We faced issues regarding the i2c data line getting stuck low (see GPIO stops working after several hours) resulting in a “bus busy” error from the Qualcomm i2c driver in the kernel log. We never really found a conclusive answer either. In general, cutting down on i2c traffic seemed to do the trick (i.e no polling).
Also, which module are you using? We’ve been testing with a WP85 on release 15 firmware and a fork of Legato 18.04.0. I have yet to test release 16 of the WP85 firmware but I’m optimistic that it could improve i2c performance.