Pirated licenses do make problems in Mach3. Not in regular intervals, tho
Even running of parallel port, I never had any issue with Mach3 (proud owner of the legal license for decades).

I know of many broken bits when using pirated licenses. And blacklisted ones are:
Code:
Schopler
Juberian
Allison
Scanners
bassam
PAPA FABIO
Ivan Todosijevic
Sompob
Advanced Control Tech (ACT)
MaoA~A ¯Ðtonar
rebecca crans
Vortech CNC
Jeff Sandstrom
Maksim Amvtonar