[Nekojinn]

Hewwo.
Using Invigorate on myself doesn't seem to give me STR HP, keep in mind my scaled str is 58.44 and my Invig is 3/3, so it should increase a bit.
Without Invig

With Invig

You can also observe that my FP did not increase from more will, however...



After a couple actions (basic attack, a few wild shapes, but I made sure to exit wildshape before taking the screenshot.)
My FP did increase, and I can only assume it was from increased Will.

I was also told that items that increase STR do not give STR HP either, but I cannot confirm nor deny this since I don't have any str giving items to test it with.

All of these screenshots were taken on live server, of course!

[Rendar]

Hewwo.
Using Invigorate on myself doesn't seem to give me STR HP, keep in mind my scaled str is 58.44 and my Invig is 3/3, so it should increase a bit.
Without Invig

With Invig

You can also observe that my FP did not increase from more will, however...



After a couple actions (basic attack, a few wild shapes, but I made sure to exit wildshape before taking the screenshot.)
My FP did increase, and I can only assume it was from increased Will.

I was also told that items that increase STR do not give STR HP either, but I cannot confirm nor deny this since I don't have any str giving items to test it with.

All of these screenshots were taken on live server, of course!

Strength only gives HP whenever BASE strength is increased (Through stat investment, star, or trait).

Says it on the tin.

[TheGhostlyKnight]

These are more or less intentional yeah, hp increases from non Vit stats only happen from base stat increases. Same with Will and FP, I believe.