Harry Bloomfield used his keyboard to write :
Or it could just be very tough grass and never throughly dries out. We have a
few inches of soil, under which is very heavy clay. It used to flood in heavy
rain, but I put in lots of drainage to try to help prevent it. It usually
needs a week of dry warm weather, even in the summer, before it is fit to try
to cut it - so sometimes it just has to be left uncut. The first cut of 2018
was very delayed by the wet weather.

...and just to confirm it is not just me...

We are away in the caravan in a three acre field. When we arrived the
farmer had just given up on trying to mow it, because his full size
tractor / mower was constantly choking up with cuttings.