Could to much mycorrhizal granules kill rooted cutting

I just potted up a bunch of rooted cuttings and had some plant magic mycorrhizal granules to hand i thought i had a great idea of soaking the root riot cubes in water then rolling them in the granules before potting up so the whole cube was covered.

i potted about 50 cuttings and the next morning i had 6-8 completely keel over and look like they are not going to make it at all. some were very well rooted some only had a couple of legs sprouting out.

could i somehow of burnt the new roots with to much on an under established root?

More is not better dude!

just a light amount until the plant is large in bigger 45 gallon pots i use a lot but the plants going in are well vegged and have established roots. I would try just a small amount next time with a liquid root inoculant