Custom Templates overwritten temporarily after quarterly patching

Summary:

After the last quarterly updates were pushed in our production environment, the Requisition Approval notification body got reverted to the original template for few hours. This then automatically got switched to the customized version. It seems there was something in the cache which was then wiped out after some time when the customized content was pushed. Is this a known issue/limitation/functionality ? If so, what's the best way to avoid this ? What process runs which makes this change on it own.. ? Thanks

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