[GNC] Sales tax changes and posting an invoice wrong tax amounts

[christian at eliminator-rc.com]

We have a problem we ran into using Gnucash. We originally setup our tax
tables for Canada to reflect 8% PST and 5% GST. We then changed the PST to
7% back in 2019. We have an invoice where it posts the right amount to all
the accounts so the accounting side is correct. But when we post the invoice
the tax amount changes in front of our eyes to an incorrect amount. It seems
like it is still using 8% PST. Again it only happens on the printable
invoice and in the invoice details. The accounts and reports all look
correct. We got around the problem by creating a new Sales Tax Rule and
setting it directly to 7% and 5%. Now when we use the new rule and post an
invoice it uses the right amounts. Is this a common problem or is this a bug
in Gnucash?