The current issue occurs in Hero Colosseum and  is scheduled to be fixed in the upcoming update.
With the update, the number of slots you have in the figure list will be corrected to the actual expanded number, and you will be able to run the Gacha normally.

As an apology for the inconvenience caused, we plan to distribute TP medals to all users.
For the time being, we recommend not going to the Hero Colosseum, including the Shop.

<Location of Bug>
Hero Colosseum

<Time the bug was found>
After ver 1.17.00 released on November 4th

TP medals will be distributed after the temporary update. We will announce the number and timing of TP medal distribution at a later date.

Thank you for your patience.