There are some issues in 1.14.4 release for MCreator 2019.5 that I would like to point out to let you guys know about for a future fix.
1. Dirt blocks don't generate under grass blocks.
I have tried to test to see if recompiling or building the mod would fix the issue and it did not work.
I have also tried updating the block element and the actual biome element but with no success.
2. Grass blocks spawn underwater.
This may be tied to the same issue above however the grass blocks should be dirt, not grass.
3. Caves don't generate in custom dimensions.
I then used to generate in 1.12.2 (1.9.1) however after updating the mod to 2019.5 it no longer generates caves.
Issue comments
No worries, I am glad to help ;)
I was working on my Pandora mod, working on some oceans, however with testing dirt does seem to spawn but around level 55 and lower however the lower you get the higher the chance it's going to be dirt for sure. This may give you a clue on what the issue is so I thought I would let you know :D
Thank you for opening a ticket as asked :) I will do my best to fix this ASAP.