We discovered that Keyman for iOS 14.0.278 (released yesterday) has a bug with keyboard switching. We have buit and submutted an urgent patch for this problem and as of writing this we are waiting for Apple to complete their App Store review process for the update. The update should be available as soon as Apple have completed their review.
We are very sorry that we missed this.
More detail: fix(ios): keyboard swapping 馃崚 by mcdurdin 路 Pull Request #5476 路 keymanapp/keyman 路 GitHub