IBKR plugin gets stuck on CBOE symbols on weekends

On weekends (or at least the last two weekends), certain CBOE index symbols will never finish backfilling, even on a short time frame, e.g.:

This causes two problems:

  1. The IB plugin gets "stuck" backfilling one of those symbols. The user has to manually cancel the backfill to force the plugin to move to the next symbol.

  2. After reconnecting the IB plugin, it again reattempts to backfill the CBOE symbol, even if that symbol is not active or in the realtime chart window, causing it to get stuck again. This also happens if AmiBroker and TWS are restarted, so there does not appear to be a way to get the plugin to "forget" about that pesky symbol.

Is there a workaround, other than just cancelling that particular backfill?