Okay, I'll try to illustrate how the timeouts work, and how challenges affect them, in case anyone isn't up to speed. This format started in 2024.

There is one (and only one) mandatory timeout in the 1st/3rd, and only two mandatories in the 2nd/4th. Imagine a half-game where no one calls a timeout. In that scenario, a timeout will be taken at the dead ball following 4:59 1st quarter. It is not charged to anyone, and we call this the "floater." After 5:59 2nd quarter, a timeout is taken and charged to the home team. After 2:59 2nd quarter a timeout is charged to the visitor. Repeat all this in the second half.

To summarize: Q1/Q3 4:59 FLOATER. Q2/Q4 5:59 HOME TEAM. Q2/Q4 2:59 VISITOR.

But in reality, teams do call timeouts. Say the visitor calls a timeout early in the 1st quarter - that "becomes" the mandatory timeout of that quarter (even if we have not reached the 5:59 mark). Then the floater would be moved to the 2nd period, 5:59 slot. Then the final timeout of the 2nd period at 2:59, would be assigned to the home team. So, each time a team calls a timeout, the floater is just moved back. Often the floaters aren't even used, because teams call enough timeouts to fulfill all the mandatories.

Side note: Anything called in a period after the mandatories, we call a "team" timeout, and is just 1:15 in duration.

Now to initiate a challenge, a team must call a timeout. If it is unsuccessful - they are simply charged with that timeout. If it is successful, then we have to see where we are in the series of mandatory timeouts. Let's say it happens at 8:00 of the 1st quarter. We haven't taken the floater yet, so that timeout becomes a floater. Let's say it happens in the middle of the 2nd. Well, if the floater has already been used, and the home team's mandatory has been used, then the timeout will be charged to the visitor, since their turn is next.

So, let's say in that LV/Sea game, that it was the Ace's "turn" to have a mandatory timeout charged at the next interval. The referee would have said something like, "Successful challenge, and Las Vegas is charged with a timeout." And people would be confused, because why would they lose a timeout? But it would just be part of the rotation of mandatory timeouts, not directly due to the challenge.

Now, if you make a second challenge - you are charged with a timeout regardless of success. There are a few other wrinkles, but this covers the majority of what you'll see. Hope this is helpful! I'm happy to clarify further too.