When I take date info into a mail merge the day increases by two

I am using libre base and libre writer. When i use date fields from the database in the mailmerge the day component increases by two days. The month and year components of the dates are not changed. The fields in the database file are all in DATE format. Another strange thing is that when the database fields are VARCHAR from the inception of the table the date is brought into mailmerge correctly. However if the table was built with DATE format and then edited to VARCHAR as a workaround the date still changes by two days. Any help much appreciated. Have transitioned to base from spreadsheets with large data sets .thank you

See this answer, Mail merge bug in LO 25.8 - #3 by PKG

But see also - tdf#168919, which talks about the same problem in 25.8.2.2 (at least that’s what was mentioned in the metadata there); so we need to know the version to tell for sure.