diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 370221f8..852558fb 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -206,7 +206,7 @@ jobs:
       - if: ${{ matrix.pm == 'pnpm' }}
         run: |
           npm install -g pnpm
-          pnpm add  "git+${{ github.repositoryUrl }}#${{ github.ref }}"
+          pnpm add "${{ github.repositoryUrl }}#${{ github.ref }}"
         env:
           NPM_CONFIG_LOGLEVEL: verbose
 
@@ -215,7 +215,8 @@ jobs:
           npm install -g yarn
           yarn set version stable
           yarn install
-          yarn add "git+${{ github.repositoryUrl }}#${{ github.ref }}"
+          # seems like yarn doesn't like using pull request branches of the form #pull/<number>/merge
+          yarn add "zeromq@${{ github.repositoryUrl }}#${{ github.head_ref || github.ref}}"
         env:
           YARN_ENABLE_IMMUTABLE_INSTALLS: false
           YARN_ENABLE_INLINE_BUILDS: true