Here's the two ESPs in question, along with the dyndolod.esm, dyndolod.esp and the full logfile.
The two files have had their records compressed, the ESL flag added from scratch, since I missed making a backup of them when i removed the ESL flag.
However, the issue could be recreated. Latest logfile entry is the run in question.
Skyrim SE 1.5.62.0.8, DynDOLOD 2.69 SE decided to try out `Myrkvior - The Flora of Skyrim` and flagged the optional ESPs as ESL, renumbering where necesary, as I usually do. After updating to 2.69 and recreating DynDOLOD from scratch, it turned out `DynDOLOD.esm` included two of the optional ESPs from Myrkvior as masters - see screenshot. Log can be found here Will remove the ESL flags from the plugins in question and update this post whether it solved the issue.