Thanks a lot....and sorry for my second post...

The bars don't disappear with the Fail Operational option - this is all detailed in the FCTM and FCOM2.

 

I tried with the option "fail pass" and i't the same! 2 nav on ILS freq, both FD on, AP disengage.. the light APP in the MCP disappears, the FD left remain MASTER the right FD not in master, and at 50 AGL the bars doesn't disappear and remains on ground till I swich them off

In IAN approach the FD disappear but not in an ILS Approach. This is a real bug, incredible that many users had not notice this issue.

Truth be told I just don't look at the PFD at that point.

I'll have to check on my next trip to be sure but I'm pretty certain the FD bars do disappear at 50' RA, at least on a single autopilot approach.  We don't do dual autopilot approaches so I couldn't tell you if they do or not in that case.