I think I remember Glide saying that for now dates need to be entered in MM/DD/YYYY format. YYYY/MM/DD and ISO should work too. In they future I think they will try to get the region settings from the sheet.
Does the date show correctly on a phone? The calendar uses the device’s regional local settings for displaying the date. The same app will show the differently in the US compared to Europe. What region is your browser set to?
I would set the date in US, Y/M/D, or ISO in the sheet, then adjust the formatting of the date in the data tab.
I don’t know if Glide has changed anything regarding what I mentioned earlier. If dates are coming from a glide date picker, then you should be fine, but if you are manually typing dates in your sheet, then sometimes they can be recognized in USA format. I always stress, especially when entering dates manually in the sheet, to make sure you are using mm/dd/yyyy or yyyy/mm/dd. I personally haven’t had any of these issues, so I don’t know how others have worked around it. It seems to be less of a problem compared to several months ago, so something must have been fixed. If you have any screenshots from your sheet and the glide editor, that might help. Also try to include shots of the date settings in the glide editor and what you have set for the column formatting in the sheet. Also the underlying value when you click on a date cell in the google sheet.