two encodes simultaneous on one esp32, one or other but not both work

Hi, I have a dual encoder (two encoders) connected to micropython on my esp32.
If I connect one or the other it works as expected.
however if I try to setup both at the same time, the first defined encoder works
the second one barly at all, ie it may work if you spin it real fast bot mostly it won't

is there some contention issue because they may be sharing interupts ?
please help.