Hi RWS and welcome to the forum
The only problem with grass treatments with that I know of is long lasting herbicide treatments. You should be fine with your grass clippings.
You may well know this, but just for any inexperienced readers, grass clippings need to be mixed with other waste. Shredded paper works well, but anything other than more very soft green stuff will help. It gets the air in and stops the grass collapsing into a slimy lump, instead of rotting nicely into compost.