Right window operates with left switch. Left window operates part time this is on a 99 Ranger

 

So the left switch operates the passenger window rather than the driver side? Left window operates part time with right switch? Very weird. I don't understand why it'd be reversed operation unless you had it put in aftermarket. But as for part time working for a switch check the contacts on the switch. pull the door panel off and remove the bezel/switch assembly and clean the contacts.

 

The switches do wear out my buddy had one that the plastic melted internally and eventually started arking and blew the fuse you may have either dirty contacts or the switches are on their way out the switches wire to one master plug so if you have bad contacts its a long shot but could possibly be hitting other bare metal inside causing it to operate the opposite window. The switches are fairly cheap you could try one from a junkyard to see if it helps.