Word-Specific Notes

A table cell's paragraph style can outrank the table style's own font color

This is a structural Word behavior, not a bug: if a header row's cells don't have their own explicit paragraph style (falling back to "Normal"), and your template's own "Normal" style has an explicit font color set on it, that color can win over the table style's own color for that row - Word's own formatting priority always resolves in this order, from lowest to highest: table style, numbering, paragraph style, character style, then direct formatting.

What to do about it: this can't be fixed from the table style side, because the table style itself is correct - it's being outranked. The practical fix lives in the template: avoid setting an explicit color directly on "Normal" (or use a dedicated style or direct formatting for body text instead), since "Normal" is also the implicit default paragraph style inside table cells unless a table's own paragraphs are explicitly given another style.