I had a few large branches from a bougainvillea and chaya miracle spinach that I ended up splitting into smaller cuttings which meant that for some of them the tips and tops were exposed because I had to cut them in halves, thirds whatever. I notice that my cuttings would shoot leaves out or even root but the wounded tops would slowly start to decompose or rot while the bottom half of the plant was still healthy

My solution to this was to just cut the tips down to until I found healthy tissue but then this left another fresh open wound at the top and I would find that wound rotting down again to the point where i just has to keep cutting until the stem was basically a little stump.

What can I do to keep this from happening?

Also is it not advised to make several cuttings out of one long branch?