Inconsistent highlight color for casts

[jketema]

Describe the bug
Casts are not consistently colored. Sometimes they are green-ish and sometimes blue-ish.

Version
The CodeQL and VS Code version in which the bug occurs.

CodeQL extension version: 1.6.0
CodeQL CLI version: 2.8.2
Platform: darwin arm64

Version: 1.65.0 (Universal)
Commit: b5205cc8eb4fbaa726835538cd82372cc0222d43
Date: 2022-03-02T11:11:20.886Z
Electron: 13.5.2
Chromium: 91.0.4472.164
Node.js: 14.16.0
V8: 9.1.269.39-electron.0
OS: Darwin arm64 21.3.0

To reproduce

1. Open ql/cpp/ql/src/Security/CWE/CWE-078/ExecTainted.ql from the CodeQL repo (current commit ID 509a3493b6b1b742bc5408c9f38e9f423b727174)
2. Scroll to the bottom
3. In the following line

   select sinkAsArgumentIndirection(sinkNode.getNode()), TPathNode1(sourceNode).(MergedPathNode), TPathNode2(sinkNode).(MergedPathNode),

   the first occurrence (MergedPathNode) is green-ish and the second blue-ish.

Expected behavior
Consistent coloring of casts.

Additional context