Fix ref leak when calling update

[bdraco]

fixes #1134
appears to be introduced in #234 (4.4.0)

[codspeed-hq]

CodSpeed Performance Report

Merging #1135 will not alter performance

_{Comparing leak2_fix (06d3dce) with master (9850454)}

Summary

✅ 244 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.68%. Comparing base (9850454) to head (06d3dce).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1135   +/-   ##
=======================================
  Coverage   98.68%   98.68%           
=======================================
  Files          27       27           
  Lines        3432     3432           
  Branches      528      528           
=======================================
  Hits         3387     3387           
  Misses         17       17           
  Partials       28       28           

Flag	Coverage Δ
CI-GHA	98.68% <ø> (ø)
MyPy	83.70% <ø> (ø)
pytest	100.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.