Wow it's been a long time since I've mobilized. So Othniel you're saying if I'm two turns from finishing Bank when I MOB the extra shields will be lost and I'll get a cavalry Instead of a bank? I've never noticed this... but then again I rarely mobilize.
No, I don't think you lose the accumulated shields but your build will be auto-switched to something allowed under mobilization. I think the article says or implies that you lose the shields but I think it's wrong.
I'm trying to recall. I just mobilized in a recent game (I play C3C) and I had several builds going for city improvements such as factories. On either the turn I mobilized or the turn after, the game auto-switched all the disallowed builds over to unit builds. I don't think I lost any accumulated shields, though.
One things for sure, though, is that if you are building something that gets the mobilization shield bonus, such as a tank, and then switch that build to something that is
allowed under mobilization but doesn't get the bonus shields, such as a bomber, then any bonus shields that were in your production box disappear.
It was interesting to me that in my game the builds were auto-switched over to
Flak units when I had Tanks available to build. Not sure why the game preferred the artillery / AA type units instead of the mainstream tanks and infantry. Of course I just manually switched the builds to things I wanted more.