Here are the poitn totals for the Mushroom side quest.
Get mushrooms = 3 points.
Sell mushrooms to Healer = 1 point.
The thing is I don't remember ever having encountered the glitched mushroom bug.... I think its because I probably collect the mushrooms later in the game.
According to some comments on various message boards/websites, its not the fact you pick up mushrooms that glitches the game, but the amount of mushrooms you pick up. Some sites say to not pick up anymore than 75 mushrooms. If you pick up too many it can cause other really strange glitches apparently. Someone says a bunch of random messages will start popping up or something.
http://vogons.zetafleet.com/viewtopic.php?t=23036 This topic has a better explanation of what causes the garbled text though;
"I just found out what caused it. It is a bug in the game, but not caused by the long name.
It happens, when you're encumbered (carrying too much weight) and save you're game while encumbered. When you restore any game after that (except savegames before you became encumbered), you hit the bug.
Well, irritating, but at least it's solved now."
So basically what this means if you collect the mushrooms, or know you will be encumbered by anything else, go sell the stuff off or get rid of it, or up your stats, before saving.