Bug fix: Manually create serialized stock

[SchrodingersGat]

• fixes bug which extraced location as a string, rather than the model instance
• bug was introduced in [Refactor] Serial generation #8246

[netlify]

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Name	Link
🔨 Latest commit	91937f0
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.28%. Comparing base (9e0a4c6) to head (91937f0).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8306      +/-   ##
==========================================
- Coverage   84.28%   84.28%   -0.01%     
==========================================
  Files        1165     1165              
  Lines       52771    52770       -1     
  Branches     1931     1931              
==========================================
- Hits        44479    44477       -2     
- Misses       7808     7809       +1     
  Partials      484      484              

Flag	Coverage Δ
backend	85.93% <100.00%> (-0.01%)	⬇️

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