diff --git a/.github/workflows/check-current-testthat.yaml b/.github/workflows/check-current-testthat.yaml
index 676a01e04..0a318cc8d 100644
--- a/.github/workflows/check-current-testthat.yaml
+++ b/.github/workflows/check-current-testthat.yaml
@@ -29,10 +29,11 @@
 
 on:
   pull_request:
-    # run in each PR in this repo
+    # run in each PR in this repo (1 worker, see matrix logic below)
     branches: '**'
   push:
-    branches: '**'
+    # only on main; pushing to a PR branch is already covered by pull_request above
+    branches: [main]
   schedule:
     # also run a schedule everyday at 1 AM.
     # this is to check that all dependencies are still available (see R/zzz.R)