Glad I could help you ...

That inky-stuff is becoming more and more nasty. Normally IK is very usefull for posing if in the main figure. But as conforming clothes are build to follow this figure they need no IK at all.

But this problem is build in since the early poser versions and made by the poser company('s) themself.
For example using the p4fboots with posette (p4), both originally from metacreations. If you bend the toe's of posette the boots will not follow. This is cause active IK in the boots.
I didn't realize that for year's until I got heavy problems with V4 and boots with IK on. The problems are from not conforming correct over not bending and making funny movements up to that "nailing and breaking" problem like in you picture.
I found that the Ik was the troublemaker and, what wonder, without IK also that old p4 thingies work correct.

So the problem is a old one (like most of the poser problems) but tends to be figure dependend more or less dangerous.

If you have poke-througs might be you have to correct the joints a bit. Otherwise if the problem is only at the toe, make them invisible. Other than in real life poser people need no existing toe and/or feet inside the shoes ... or other bodyparts inside as far as the cloth is covering the part completely ... :-)

You are somewhat brave, starting with such heavy things like boots and going on with relatively easy backpacks and such accessories ... ok, is our german virtue "Kopf einziehen und mitten rein ins Gewühl" ... much luck for the backpack ...