ColdFusion does not support Big Sur. Before upgrading the OS, check the support matrix.
Adobe ColdFusion Builder (2018 release) and ColdFusion Builder (2016 release) are NOT COMPATIBLE with Big Sur.
If you launch ColdFusion Builder on macOS Big Sur (macOS 11), it behaves unexpectedly and produces exceptions.
We are working on making ColdFusion Builder to be compatible with Big Sur.
Meanwhile, you can review the current system requirements for ColdFusion Builder.