Quest Mode deck strange behavior

[Aetherborn Horror]

So I've been creating a rendition of the Kaladesh/Aether Revolt matches (from Duels).

While the duels have been working smoothly so far (no errors, crashes, etc.), something's bothered me while checking one of the decks used for the AI- The deck says it has only 58 cards. I checked and compared my list to the one shown, and it turns out that the Forge one is missing 2 Meandering Rivers (although it still appears to have 4 in the .dck file).

I tried to edit the deck file by swapping cards around, but it seems to always ended up less than 60- Usually around 56~58 cards.

So what actually happened? There's no error report dialogue showing up, so I guess I just did something wrong in building the deck file. I'm still new to Forge (and MtG in general, just learned to play 3 weeks ago), so please tell me if I'm missing something.

Decklist:

| Open

[duel]
[metadata]
Name=Chief Baral 3
Title=Chief Baral
Difficulty=hard
Description="Chief Baral commands a strong line of White creatures and vehicles."
Deck Type=constructed
[Main]
1 Aerial Modification
2 Aether Meltdown
2 Aethersphere Harvester
1 Angel of Invention
2 Baral's Expertise
2 Bastion Inventor
2 Bonded Construct
1 Cataclysmic Gearhulk
1 Caught in the Brights
2 Cloudblazer
2 Consulate Dreadnought
2 Glacial Fortress
2 Implement of Improvement
9 Island|KLD
4 Meandering River
2 Peacewalker Colossus
8 Plains|KLD
2 Prairie Stream
2 Reverse Engineer
1 Skysovereign, Consul Flagship
2 Spire Patrol
2 Sram, Senior Edificer
2 Sram's Expertise
2 Trophy Mage
2 Trusty Companion
[sideboard]

[twosat]

I have the same problem through all play modes in the desktop version.
It looks like all preconstructed decks at some point have this problem.

I think i narrowed it a little bit down: If in the deck file there was a line like
12 island, then somtetimes forge ommitted some islands. When i changed this to 12 island|ZEN|1, all are there.

To test this assumption i reworked a few preconstucted decks and it worked for all.
Maybe a developer could look into this.