Indeed. The private lessons allegedly caused a stir as it was done without LT asking Leung Sheung's permission - and so was seen as generation jumping.
The MA Hero interview with YM mentioned LT was a closed door student... and when published Yip Man had no problem with the print - no correction or retraction asked for.
YM attended LT's WT events, was a guest at LT's wedding, etc. There was clearly a relationship there.