Smart Layout symbol instance not resizing after text override — what to check

I'm using Smart Layout on a symbol master in Sketch (recent version on macOS) so that instances resize automatically when text overrides change the content length — for example, a button whose width should follow its label. In my document, the instance keeps its original bounds after I edit the override text, and the label overflows instead of the background growing.

The symbol master has Smart Layout set to horizontal, left-to-right. Inside the symbol there is a text layer plus a background shape, and the background has resizing constraints applied. I understand Smart Layout only applies to symbols, not plain groups, and that nested-layer constraints can conflict with the expected resize direction, but I'm not sure which setting is actually blocking the behavior.

The document is also shared with teammates who may be on different Sketch versions, and I've read that resizing behavior can differ across releases.

Which Inspector settings on the symbol master versus the nested layers determine whether the instance resizes? Could a version mismatch between collaborators cause Smart Layout to be ignored? What is the most reliable way to verify the configuration is correct?