LucasArts caught that and pulled the Tier 4 Platinum arena crate completely. Here's what the crate shop looked like now:
The price of the other crates dropped, either because that's what happens when you reach a certain level, or LucasArts felt sorry for us and slashed the prices to make up for not giving us the Tier 4 Platinums anymore. According to their support team, there is an app update coming on April 30 to fix this and many more bugs, but it doesn't look like they'll make that deadline.
Correction on May 2: different players will have different arena crate costs. The player who had the Tier 2 Silver cost of 675 in the top photo is further along in their progress in the campaign mission. The player who has a Tier 2 Silver cost of 450 has not gotten as far in the campaign mission, so their costs are lower. Neither player, however, can see Tier 4 Platinum arena crates, even after the software update on May 1.
If you were lucky enough to buy some Tier 4 Platinums, they would have looked something like these:
Check out that first crate -- it has the coveted Medal of Alderaan, which is needed for Leia to promote to Tier 5, and is not available through regular missions. Hopefully LucasArts will fix this soon, but in the meantime, enjoy the game and thanks for reading!