Plugin upgrade breaks recognition of build tasks when using status bar button

Brief Issue Summary

With a default built task configured from task.json, pressing the Build button from the status bar now reveals a menu rather than running the default build task. The menu does not appear to contain the default build task as an option. This was not a problem in 1.12.27 - it would launch the default task as expected.

Build button:

Revealed menu after pressing button:

The "Cmake:Build Task" option in the workspace settings is set.

CMake Tools Diagnostics

{
  "os": "linux",
  "vscodeVersion": "1.74.3",
  "cmtVersion": "1.13.40",
  "configurations": [
    {
      "folder": "/home/jon/git/proto",
      "cmakeVersion": "3.18.4",
      "configured": true,
      "generator": "Unix Makefiles",
      "usesPresets": false,
      "compilers": {
        "C": "/bin/x86_64-linux-gnu-gcc-10",
        "CXX": "/bin/x86_64-linux-gnu-g++-10"
      }
    }
  ],
  "cpptoolsIntegration": {
    "isReady": true,
    "hasCodeModel": true,
    "activeBuildType": "Debug",
    "buildTypesSeen": [
      "Debug"
    ],
    "requests": [],
    "responses": [],
    "partialMatches": [],
    "targetCount": 1,
    "executablesCount": 0,
    "librariesCount": 1,
    "targets": [
      {
        "name": "rpc",
        "type": "STATIC_LIBRARY"
      }
    ]
  },
  "settings": [
    {
      "communicationMode": "automatic",
      "useCMakePresets": "auto",
      "configureOnOpen": true
    }
  ]
}

Debug Log

(no relevant input generated when the menu comes up)

Additional Information

Below is the contents of my tasks.json. Pressing ctrl+shift+b builds as expected.

{
  // See https://go.microsoft.com/fwlink/?LinkId=733558
  // for the documentation about the tasks.json format
  "version": "2.0.0",
  "tasks": [
    {
      "label": "build current target",
      "type": "shell",
      "options": {
        "cwd": "${workspaceRoot}/build"
      },
      "command": "make -j`nproc` ${command:cmake.buildTargetName}",
      "problemMatcher": [],
      "group": {
        "kind": "build",
        "isDefault": true
      }
    },
  ]
}

Setting the default built task again (ctrl+shift+p -> Configure Default Build Task) does not resolve the problem.

Start by reproducing the issue with the provided tasks.json, the status-bar Build button, and the CMake Tools diagnostics; compare it with Ctrl+Shift+B, which works. Trace the status-bar build command and default-task discovery path, then verify that the configured default task runs from the button and that the menu includes it.