I can not trade with the old villiagers whose versions are below 1.14

My save is updated from the 1.13.2  and I played it in 1.14.2 for some time.

So there are two kinds of villiagers in game : old villiagers from 1.13.2 and new villiagers born in 1.14

Today  I found it that I can not trade with the old villiagers whose versions are below 1.14

Some of the old villiagers dont have block to work ,but i still can trade with them in 1.14.2

but this does not work in 1.14.3 Pre-Release-2 now

When I tried to trade with them,  the GUI of trading just opens and closes itself with a flash

Is this a new bug ? 

Thanks !