I have just confirmed that for SISO configuration maximum master clock rate which for which RX bursts timing precision is correct is 378 MHz, which gives sampling rate of 47.25 MHz for both channels (1xTX and 1xRX).
For MIMO basically one should use twice lower master clock rate, which gives sampling rate of 23.625 MHz for all four channels (2xTX and 2xRX). This configuration looks correct for RX channel 1, but ca. 20% of RX bursts received via RX channel 0 has still incorrect timing. This actually seems to be totally another bug (not depending on sample rate), which I have already reported on LimeSuite github tracker and on this forum. I find this issue very serious and hope that somebody from Lime Team will be assigned to this soon.