GDS/PRS systems cannot handle either an apostrophe nor a hyphen, so this is normal. In some cases airlines normalize the name against another record just for display purposes, but United's method of smashing everything together is normal and is consistent with how all airlines must send APIS data to DHS.

If you're having trouble with PreCheck then your best bet is to contact United at the time it happens to have them investigate. The phone agents aren't good about this and usually parrot back a line about documents matching exactly. I've found Twitter reps to be a bit better for it. One thing to keep in mind is that PreCheck is not guaranteed and the TSA may choose to withhold it arbitrarily on a flight-by-flight basis. If it only happened once then I'm not sure I would worry about it until it happens again. But either way the name issue is a red herring here. Was there anything at all different about how you booked the ticket that didn't have PreCheck? Used a travel agent you weren't using before? etc.