Hmm, had a look at your images and from what I can see they don't look like cysts of cb - but there's very little detail. I agree that they don't look or indeed 'react' like Phoma may be expected to when 'squashed' and ruptured....
What we need is greater detail
, not necessarily magnification - I think x400 is easily enough for the purposes of ID.
Basically try to separate some of the spheroids from the moss with dissecting needles - easily done under a stereo 'scope but not otherwise unfortunately. Then squash them as evenly and thinly
as possible between slide and cover-slip and use as any water-mount.
It may be possible that they are moss propagules rather than sexually-reproductive structures (propagule here being clonal of course) also. Their position on both stem and
leaf I think rules out reproductive organs. Their apparent lack of damage or effect on the tissue adjacent I suspect precludes their being Phoma or similar.
As seen the images are the limiting factor - have a few more tries to improve them if you can - it only takes one good image to give a whole host of clues!
Oh yes, the images were not with my current Orthoplan, rather they were with a very nice Chinese generic infinity 'scope with Plan objectives sold as the 'SP200' by the folk at Brunel Microscopes. But then along came the mighty Orthoplan and then a nice little SM-LUX and my conversion to Leitz began!