What I found is the PB2.6 and earlier versions and using some LCDs, PB is too fast (20m xtal) in the initialisation routine for the LCD, and I have had to edit the appropriate file and insert some NOPs, doing this and the LCDs work fine.
Before any suggests to use the LCD US defines, these did not appear to work during the initialisation routine, they appear to only come in to effect later. There was a post recently about LCDs if I remember and that also had avice about editing the file. I assume that PB3 has the same routines.