Boar spell Charge ranks 1, 2, 3, 4, 5 are considered a “different” spell than Charge rank 6.
This means, that means if you have a boar who has a 4 skills (the limit for active skills for a hunter pet), with Charge 5, you will not be able to teach Charge 6 (game considers it a new spell, rather than a new rank).
If you reset all pet skills at the Pet Trainer and teach Charge 6 right away the boar will learn it, but will show the previous ranks of Charge as not learned (pet training window). Also, a boar can have Charge 5 and Charge 6 at the same time (though of course it can only use one since they share CD).
I leveled my Boar pet to 60. It had Bite 6, Charge 5, Dash 2, Greater Stamina 8, Growl 6, Natural Armor 7. I then stabled it and tamed Plagued Swine and kept using it till I learned its Charge 6. Then I swapped to my original Boar and attempted to teach it Charge 6 however I kept getting the error “Your pet can’t learn any more skills”. I then successfully taught it Dash 3 (which replaced Dash 2) and Growl 7 (which replaced Growl 6). Tried teaching Charge 6 again and same error. The Boar currently has 37 Training Points, and Charge 6 costs 25, so I have enough. After paying 10s to respect the pet I was able to teach it Charge 6 and all remaining skills I listed earlier. Shouldn’t need to respect pet to upgrade Charge 5 to Charge 6.
I see. So that sort of clarifies the OP (from 2019) that for some reason Rank 6 of Charge (maybe charge specifically or for Boars specifically) seems to count as a separate skill and requires respecc’ing your pet?
Are you able to have both Charge Rank 5 and Charge Rank 6 active?
Yeah that’s what it looks like. No, after respeccing and immediately learning Charge 6, all lower ranks (1-5) are “already learned” - grayed out and cannot learn them anymore.