Bug?: Can't release "Average surfaces" option in Match dialog

In the latest release ((6.18.19253.10261, 09/10/2019)) I suddenly can’t release the “Average surfaces” option in the Match dialog. I don’t know how I got here, but here I am.

// Rolf

Hello - that is grayed out when it is not available - one edge is trimmed. It will not be used if gray.