Document flag incompatibilty in docs

website/docs/cli/commands/test.mdx

@@ -32,7 +32,7 @@ The following options apply to the Terraform `terraform test` command:
 
 * `-json` - Displays machine-readable JSON output for your testing results.
 
-* `-junit-xml=<output file path>` - Saves a test report in JUnit XML format to the specified file. The file path must be relative or absolute.
+* `-junit-xml=<output file path>` - Saves a test report in JUnit XML format to the specified file. This is currently incompatible with remote test execution using the the `-cloud-run` option. The file path must be relative or absolute.
 
 * `-test-directory=<relative directory>` - Overrides the directory that Terraform looks into for test files. Note that Terraform always loads testing files within the main configuration directory. The default testing directory is `tests`.