I haven’t - my remortgage is due in November this year but I went part time in January 2023. So I can’t say for sure, but I would imagine they will want an up to date income so yes feasibly they could have an issue depending on what they think you can afford. When is the remortgage due? Maybe try one of those mortgage calculators using what you think you’ll earn if part time and that should give you an idea of whether you may have an issue or not.
I’m self employed work 2 days but husband is employed working full time. They just asked for my latest tax return and his last pay slip and that was it as didn’t need to look into anything as just remortgaged with them again. We did have to fill out where all our money goes each month in a spreadsheet they provided but was pretty simple and very rough outgoings not strict!