I have used commercial products in Australia with a similar base of ingredients.
It comes as a concentrate, with low biological activity until you dilute it.
Once you make up a tank mix it becomes active, as the concentrate suppresses activity.
I mainly used it on container plants, no problems. But I didn't brew it.
Later I switched to the dry fertiliser version of the same thing.
I did have problems when I added extra microbes to the mix and brewed those.
Basically I got a population of unusual microbes in my pots, that I have never seen before.
I would watch out for too much microbe activity.
You may not need to brew the mix at all, or as much as they say, it should also stimulate the soil flora already there.
You may want to also think about what you use it on, i.e. maybe not directly on leafy greens or vegetables you eat raw, or just prior to fruit harvest.
Also Composts are pretty variable in their composition and maturation. The microbes are going to be variable in different composts, and at different stages.
Most of the other ingredients are pretty standardised, i.e. Kelp, Humates, Molasses etc.
There are various brands of these, some better than others.
There were problems with Fish fertiliser being sprayed on Citrus for juicing, and microbes being carried into the juice process line.
(Well that was the story.)
I did use fish fertiliser in my fertigation, along with the kelp, humates etc but used the tank within one day and didn't let it brew.
The oils in fish fertiliser might be a problem for some plants, and if applied too strong, same as any oil spray.
The vegetable oil and the flour in the brew mix might be additional microbe food ?
To sum up, I used most of the same ingredients as liquid fertiliser drench, not sprayed on foliage, and didn't brew it.