Why retainage rate impact Zero tax

Summary:

Hi. In R12 I have noticed for retainage release invoices sometimes users face issues in adding/calculating zero tax. An error message will pop when they select a zero tax code. most of the time the retainage rate at po level is 0%. Once we changed the rate to an amount which is more than 0% we are able to update zero tax. Could you please explain this behavior. We have suggested this workaround multiple times and it worked.

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Version (include the version you are using, if applicable):

R12

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