I missed it in the release notes, but there's a breaking change in the ota component in ESPHome 2024.6.0. I figured I'd save folks some time and share the fix here.
If your OTA config looks like this;
...
ota:
password: "*************"
num_tries: 3
safe_mode: on
...
Now you'll need to add a platform key to start a list, and either comment out the other option or move them to a new component.