HP CP3505 missing black portion of lower half of last page ONLY of print job

[TEKK09]

Really strange one, hope someone has seen this...see attachments. I got this after replacing the right side slide lever, but think it may have something to do with rough treatment. The top lever on the left side (for the black unit) was also broken and replaced. It only happens on the LAST PAGE of a print job. If it's a one page job, that page will also be the last page and will be missing the lower half, black only, colors seem to be fine. Examples show page 5 of 6 fine, but page 6 of 6 affected. I should say MOST of the black portion is missing, it's very light, like the transfer shut off early.