Inconsistency in collection.json

[HugoKornelis]

I use the collection.json file that Firestone produces for my missing dust tracker. That works great (so thanks for making it available and thanks for the quick response to my previous report).
However, I noticed a weird inconsistency in this file. I can work around it so it as at least to me not high priority. But you might still want to know.

There is a set of 3,848 uncollectible cards that sometimes are, sometimes are not included in this file. If they are included, they all are. If they are not, then none are. These files are all from the LETTUCE set. Their CardIDs start with BARL (49)_, LETL (1614), LT21 through LT25 (2,164), or SWL (21).
I have not (yet?) been able to identify a pattern in when these cards are included in Collection.json and when they are not.

EDIT: After some further digging, I found out that these cards are apparently all related to Mercenaries. I also found out that they are not all uncollectible, I encountered a few collectible mercenaries cards as well.

[sebastientromp]

Thanks for the report! I Do you have a couple of IDs that I could use to track things?

[HugoKornelis]

Sure, no problem at all!

[{"CardID":"BARL_009H_02","dbfId":70854,"CardName":"War Master Voone","Rarity":"Epic"},{"CardID":"LETL_001P9_02","dbfId":67103,"CardName":"Banshee Bolt 2"},
{"CardID":"LT23_021E3_04","dbfId":86363,"CardName":"Fel Cauldron {0}"},{"CardID":"SWL_06H_01","dbfId":72859,"CardName":"Cornelius Roame","Rarity":"Rare"}]