diff --git a/.gitignore b/.gitignore
index cc770a8f..7583132c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,4 +14,5 @@ docs/_build/
 build/
 virtualenv/
 venv*/
+env*/
 example.sqlite
diff --git a/src/apscheduler/datastores/mongodb.py b/src/apscheduler/datastores/mongodb.py
index 44e2b901..2aea594c 100644
--- a/src/apscheduler/datastores/mongodb.py
+++ b/src/apscheduler/datastores/mongodb.py
@@ -628,7 +628,9 @@ async def acquire_jobs(
                     )
                     async for doc in cursor:
                         task_max_running_jobs = doc["max_running_jobs"]
-                        task_job_slots_left[doc["_id"]] = doc["max_running_jobs"]
+                        task_job_slots_left[doc["_id"]] = (
+                            doc["max_running_jobs"] - doc["running_jobs"]
+                        )
 
                 acquired_jobs: list[Job] = []
                 skipped_job_ids: list[UUID] = []
@@ -688,6 +690,8 @@ async def acquire_jobs(
                         self._logger.debug(
                             "Skipping job %s because task %r has the maximum "
                             "number of %d jobs already running",
+                            job,
+                            job.task_id,
                             task_max_running_jobs,
                         )
                         skipped_job_ids.append(job.id)