Just got back into Soviets to finish off the tree - been playing US and Japanese since the merge - neither of them had this issue - all the squads show the “Level up soldier” icon - the little green box with an arrow in it.
And it is across all nationalities - wasn’t here last week!!
Doesn’t matter what squads I have, doesn’t matter what soldiers I have in them - fully maxed top ranking, or brand new recruits - they all show this.
I mean, they fixed it , by making it a permanent part of the UI for every squad. Same thing applies to the button that shows the available maps… which is completely false most of the time.