Thinking about this a bit more.
1. If you can do legless rope climbs you must have some decent strength. However I have none a few people who can do legless rope climbs with no problem but didn't really have strong abs (but they were also tall and lanky and young so bad levers for gymnastics ab work as they were non gymnastics [rec kids])
2. How often do you normally work out? You said you follow mainsite so that makes me want to think 3on1off.
3. The DL in Diane can tax the abs a bit as can the HSPU. Well for some people. It's hard to say.
4. My only guess is Diane taxed your abs a bit and even though there was a day of rest, the rope climb sprints hit them again a bit.
5. When you climb a rope, you actually have to create body tension just like when doing pullups especially legless. I wouldn't say they work the abs heavily like L or straddle rope climbs but they do work them some.
6. Did you do anything funky like kip the rope climb hand grabs?
Kinda stupified the more I think of it.
Technically running does hit the abs a bit.
So you have Friday of doing DL.
Sat the 5k, which isn't much but each step there is some impact, a little.
Sun the rope climbs and sprints (which have way more impact per steps). I've never been sore from sprinting in my abs.