Pack Version:
Version 1.2.2 (FTB Launcher)

Description:
First time using the Nether Cake, place me in a lava lake in nether, 4 blocks down in it. The lava lake is 7 block deep at that point. the overworld cake spawned 2 blocks under the 3x3 obsidian. Don't know if that is normal.

Expected Behavior:
Spawn on safe ground, without being engulfed in lava.

Steps To Reproduce:
Steps to reproduce are below the link. In the link, there is backups of my world, both before and after the discovering the bug.
Newest Backup: Backup from after encountering the bug.
Second Newest Backup: Backup from before encountering the bug.
https://drive.google.com/drive/folders/1N_n52McV2d66Joe52ojBmOAQLS2f3tFi?usp=sharing

In Newest Backup, if you Right-Click the Nether Cake in either survival or creative, you will get teleported to the 3x3 obsidian platform, 4 blocks down in lava. The Overworld Cake will be 2 blocks under the obsidian.

In Second Newest Backup, if you place the Nether Cake in Creative mode, and Right-Click the cake (still in Creative mode), you will be teleported into a Lava Lake. If using /home, and then using the cake again, you will be teleported into bottom bedrock (and thus destroying 1 bedrock and 1 netherrack block), and then immediately teleported above top bedrock. This will repeat as many times you use the Right-Click a Nether Cake.

Screenshots:

Hello, yes there were several issues with the teleportation logic of cakes in 1.2.2. This was fixed some time ago in the development version of the pack, however (see for example #725).

Our fork of Dimensional Edibles fixes spawn-below-map and spawn-in-lava issues, as well as improvements to item tooltips and overlays. If updating from an older version, use the /de invalidate command to reset a bad spawn position for a target player and dimension. This command requires operator permissions in a dedicated server environment.

Theoretically you can drop-in-replace Dimensional Edibles with our fork, but you would also want to grab the updated config file.

That said, I would urge you to instead just update to dev. This has our fork of DimensionalEdibles and the config file already configured, plus everything else we've done in the nearly two years since the release of 1.2.2.

There is no server involved if you are playing SP. You would load in and issue the command /de invalidate PlayerName -1 and it would clear the bad cached destination in the Nether for the player named "PlayerName". The next piece of Nether Cake you eat would re-compute where to teleport you inside of the Nether. The corrected teleport logic ensures that your destination is both within the vertical confines of the Nether (i.e. not above or below the bedrock) and that your body isn't placed inside of a fluid (e.g. lava).

So what I have to do, is to download server files, start up the server with my world/save, log into the server, and then type /de invalidate PlayerName -1, log out of server, put world/save into singleplayer folder?

Theoretically you can drop-in-replace Dimensional Edibles with our fork, but you would also want to grab the updated config file.
I replaced both the mod, the DimensionalEdibles.cfg and the nether cake, but still got teleported to same place. After that I deleted the nether dimension, DIM-1, and the nether cake again, and tried again. Same result; got teleported to same place.

I tried with the server (I did update the mod and .cfg there too), with /de invalidate PlayerName -1 and that worked without a problem. However, I did r-click the cake at spawn area, and not where i previously had problems. As it worked, I shut down the server, and moved the world to the singleplayer folder. I opened that world, but got teleported to the same lava lake.

So my only option now, is to go in there in creative, then remove the lava in a 5x5 area.

There is no need to world edit to fix your issue, nor is there a need to move your world to a server if you were playing in SP. The positions each player goes to in each dimension are stored locally as data on your player. The command clears the data forcing the position to be recomputed.

First, do precisely one of the following:
A) Update your client to the dev version where the mod will have been updated for you (Recommended),
OR
B) replace the Dimensional Edibles jar in your instance with the latest version of Dimensional Edibles: Omnifactory Edition and replace the config file with the one I linked in my prior message.

Second, load it up in Single Player mode just like you were playing before, and run the invalidate command targeting your character and dimension. Now the bad position is cleared from your character.

Third, eat another slice of the cake. Done.