When you open file from examples, editor does not show them. There is an error.
https://github.com/kiegroup/kogito-examples/blob/stable/kogito-usertasks-quarkus/src/main/resources/org/acme/travels/approval.bpmn
https://github.com/kiegroup/kogito-travel-agency-tutorial/blob/master/02-kogito-travel-agency/src/main/resources/org/acme/travels/travels.bpmn2

I also tried other files, not just these two. Downloaded them, tried importing in online or opening in VSCode.
To me it looks like every file is affected - https://github.com/kiegroup/kogito-travel-agency-tutorial/blob/master/06-kogito-travel-agency/src/main/resources/org/acme/travels/travels.bpmn2

Reproducible on all channel -> looks like BPMN editor related issue (something with parsing) I wasn't able to pinpoint the exact location.

Error dialog gives no information about the cause: