Captions - when applying two outputs captions not burnt in.

I created two similar H264 output presets - the only difference is one has captions burnt in and the other is clean.

If I apply them individually (ie duplicate the source with only one output) then everything works as expected howeve if I apply them as two outputs to the same clip the captions do not get burnt in on the preset with burnt-in captions. The workaround is .... to apply them individually. I have other similar H264 presets which do work.... go figure.

I tried to attach the presets but the forum won't accept them.

AME 24.2.1