Placing mod in Dev folder (as for testing during mod implementation) results in an endless "Content changed"/"reload required" message loop. If I reload, no amount of reloads removes this message. I can enable the mod in the mod list and ignore the messages, but the mod won't work in game like this.
I have tested this on two Ubuntu PCs, 18.04 and 16.04 and the behavior is exactly the same. I have tested exactly the same mod on Windows, and it works without loop - I restart the game once, and then the mod works for me.
The issue only happens with Dev and Local mods, Steam mods work fine.
This mod enables bigger camera zoom out, so you can easily test if it is working by scrolling out with mouse wheel in normal game mode. If mod works, you can scroll the whole map into your screen. Big thanks to @Cairath for helping me and providing the mod.
Here is the log snippet that happens on Ubuntu each time the game is started (and looping with reload-required), please note I've edited out user names etc:
[18:41:04.617]  [INFO] Initializing at 2019-08-08 18:41:04.616
[18:41:04.617]  [INFO] Save path: /home/<USER>/.config/unity3d/Klei/Oxygen Not Included
[18:41:04.798]  [INFO] Load mod database
[18:41:04.850]  [INFO] Latent reinstall of mod biggercamerazoomout
[18:41:04.852]  [INFO] ModLoader.dll failed to load. Either it is not present or it encountered an error
[18:41:04.852]  [INFO] Load content (DLL) for mods:
[18:41:04.852]  [INFO] Load content (Animation) for mods:
[18:41:04.852]  [INFO] Load content (Strings) for mods:
[18:41:04.983]  [INFO] Distribution platform: Steam
[18:41:04.984]  [INFO] Localization.Initialize!
[18:41:04.990]  [INFO] Load content (Translation) for mods:
[18:41:04.990]  [INFO] Register mods/Local/ and mods/Dev as mod distribution platforms
[18:41:05.008]  [INFO] Subscribe to mod biggercamerazoomout
[18:41:05.008]  [INFO] Already subscribed mod: biggercamerazoomout
[18:41:05.009]  [INFO] Uninstalling mod biggercamerazoomout
[18:41:05.026]  [INFO] Logged into Steam with ID:<ID>, NAME:<name>
[18:41:05.027]  [INFO] [Account] Requesting auth ticket from Steam
[18:41:05.032]  [INFO] Load content (LayerableFiles) for mods:
[18:41:06.057]  [INFO] [Account] Got login for user <USER>
Unloading 5 Unused Serialized files (Serialized files now loaded: 0)
Steps to Reproduce
 Install the game on Ubuntu 18.04 or 16.04  Empty your mod folder under /home/USER/.config/unity3d/Klei/Oxygen Not Included/mods  create Dev folder there  unzip the example mod and copy mod's folder into Dev  start the game  see the mod in the mod list, enable it, see the popup  restart the game  see the popup, restart the game again  restart any amount of times or basically try any combination of restarts, enabling the mod, closing, starting - no matter the steps, game constantly says that the mod has changed and it does not enable the mod if you load or start actual game
This issue has been fixed in either a future version or updated in a previous version.