May I add some words ?
... in the middle of the rod, it seems this is dry because after 4 weeks, part of the water as been evaporated (rod dehydration), that's why it's soft, and this is wrinkled and most probably not rot. I would not be afraid too much.
Looking to the bottom, it looks like if there are some roots departure. I agree with previous comments, the rooting process in water .. is a bit Dangerous (this is working with Pudica, I've done it) but to be avoid with RUBRA's.
If you root in a transparent plastic bag with a perlite/soil mix this will take perhaps a few months ... putting some hormone could help .. From my side, I root in plastic bottles .. not bad. Plastic bag is better and now I proceed like that.
At the left, this cutting is almost 1 year 1/2, (18 months) it has "refused" to root, I've been oblige to cut a bit, but now seems to be OK to grow .. LOL. The second one with the blue stick, is almost one year old, also oblige to cut ... but now that's ok, in a dry perlite sustrat. Some leaves are growing. But normaly the rot process is taking a few months (from 2 to 4 or 5) .. See bellow.
