Seriously, what's up with it? It seems to me that if a champ is within range of 2 other champs with boost treefolk it cancels itself out, and you must move both boosters away then move 1 back in to boost the champ you want. This makes no sense. Am I suppose to run only 1 type of champs with boosts, and if I have 2 only deploy 1 at a time? As a side note, never let a 20 damage champ mimic (the SL spell) your tanglefoot
Post the bug - it is a bug. Boost has always had problems with stacking, processing multiple times, canceling out, etc. And yes, having a massively damaging champ mimic a tanglefoot is just... ugh.
I've never encountered this bug, but i've encountered something similar. Sometimes, moving the unit which should be affected by Boost, into Boost's range, won't trigger Boost. You have to move the affected champion back out and in again, for it to work properly. Post this in the Bug section though, not KF.
Were you around when boost three would stack on a champ? You could move in and out of boost range and give the champ repeated, stacking speed/damage/health boosts. At one point I was testing (during an open Beta) a boost mechanic on a boost beast rank 3 champ... the target beast wound up with 100 speed after several rounds of moving in and out of boost range.