Why is my cut paste cracking within weeks?

[RozendaalArts]

Pic is from my Hibiscus which I pruned and applied the paste to 2 weeks ago. It started cracking within a week and the horizontal marks are from when I pushed it closed with my fingernails.
Same thing happened on a F. microcarpa.

The paste is definitely not dry, so does it just mean the tree is already healing, or am I applying it wrong somehow.
Is there a need to push it closed again when it cracks open like this or can I just leave it?

 

[Potawatomi13]

I can't be sure. You can take a look underneath and see. It won't hurt anything and you can reseal it after.

 

[Brian Van Fleet]

Because it is working. Thr cambium beneath is forming a calus and moving the paste..

 

[Glaucus]

It is cracking because the material is getting less elastic and less sticky but more brittle because of evaporation of the solvent.
As for wound healing, plants don't heal wounds. They compartmentalize the damage, then grow through it.
The wound paste interferes in a minor way with this compartmentalization. But people still swear they need wound/cut paste on bonsai. Because bonsai cuts are different from ordinary plant cuts.
But the proponents of bonsai paste cannot even agree among themselves as to why cut paste is good and why no cut paste is bad.

But if I put myself in the position of a cut paste proponent, I would say you applied too much.

 

[Dav4]

Because it is working. Thr cambium beneath is forming a calus and moving the paste..

If your tree is actively growing, this is exactly what you want to see. Honestly, I always check recently applied cut paste hoping to eventually see cracks forming in the paste around the perimeter of a recently created pruning wound.. When I don't see this after a month or two, that usually means the formation of callus has stalled and I need to figure out why.

 

[RozendaalArts]

If your tree is actively growing, this is exactly what you want to see. Honestly, I always check recently applied cut paste hoping to eventually see cracks forming in the paste around the perimeter of a recently created pruning wound.. When I don't see this after a month or two, that usually means the formation of callus has stalled and I need to figure out why.

I just didn't expect it to go so fast I guess the hormone the Japanese put in this stuff is doing its job, cuz there was a much older wound of similar size on the branch that I cut off, which I didn't put paste on, that hadn't healed at all.
So is there any need to keep pushing it closed? In case moisture can escape through those cracks

 

[Dav4]

I just didn't expect it to go so fast I guess the hormone the Japanese put in this stuff is doing its job, cuz there was a much older wound of similar size on the branch that I cut off, which I didn't put paste on, that hadn't healed at all.
So is there any need to keep pushing it closed? In case moisture can escape through those cracks

There's no harm to gently push the paste back down as long as it's pliable but not necessary in my experience. I usually just leave it alone to do it's thing. On some particularly large wounds, I may rewound the callus in late spring/early summer then reapply the cut paste.