i am having this same issue.  I have emailed support. 

After some testing, I managed to resolve this by changing the destination field in the excel sheet to "Text" type. This was set to "General" type, which may be why the zeros were trimmed - likely by excel during storage. Apparently, appsheet sends th...

Was this resolved? I have a similar issue where both fields are text and my leading zeros are being removed after a LOOKUP([Building], "Buildings", "Building Name", "Building ID"). Any advice? Thanks.

so is there a link so i can read it to perhaps solve my problem?