Since this morning (Sep 16, 2025) our private Power-Ups began blocking some functionality and logging new console errors. We do not declare or use attachment-sections, yet Trello is complaining:
An error has occurred checking the feature gate. Only the first occurrence of this error is logged.
gateName: ‘platform_moonjelly_bsc_master_killswitch’
Error: Client must be initialized before using this method
IFrameIO.ts:164 Power-Up 55a5d916446f517774210006 implements capabilities that haven’t been enabled [‘attachment-sections’]
Our code only initializes card-back-section. Nothing in our manifest or admin settings enables attachment-sections. Enabling/disabling in the admin console and adding a stub handler for this Capability have no effect. This appears to be a backend feature-gate rollout problem, but there’s nothing matching it in the Changelog page.
Can the Trello team confirm if attachment-sections enforcement was recently enabled, and whether this is a bug? It appears to have changed only as of this morning for us.
Edit: Good news – rerunning the Powerup form worked this time. So perhaps the issue was elsewhere and unrelated to these console errors. Nevertheless, it would be helpful to hear from the devs why this error is displaying on boards containing our Powerups. Is there a gating feature broken on the back end or something?