Xenon headlight alignment problem

[JS_4.8]

My mom owns a 01 4.4i - 120K miles and running great

However her headlights had recently become very dim, so I decided to replace her xenon bulbs.

Just got done with it this afternoon, replaced them with genuine Philips 4300K bulbs. Bulbs look great, however I noticed her driver side headlight is definitely pointing higher than the other side.

I never checked the alignment before I did the install, so I wasnt sure if it was something I had did. After talking to her and hearing... "ohhhh, maybe thats why people sometimes high beam me even when I dont have my brights on", I determined this problem has been around for a while lol

So parked in front of the garage in the shade, turned on the lights, opened the hood, and starting turning the adjustment knob on the drivers side healight. It was moving (ever so slowly) down until it was almost in line with the other side....and then I hear a little pop and it moved back up to where it was. I say "oh shit", because it now appears the adjustment mechanism is broken - turning the knob yields no movement of the beam as it did before.

SO...has anyone even had this happen? I am assuming the only fix is to replace the headlight (which is not an option on a 120K old car). Just curious as to why this happened, and if there is something I am missing to maybe bypass this. To be honest, the misalignment isnt THAT bad - but enough to bother some drivers and anyone with OCD (ie, me lol) crazy!!

Thanks for any replies