Perhaps this is related to the use of System.IO… See this post here.
System.IO - #26 by Epic_Santiago
The could be related to some configuration changes to the cloud environment that support may not have been informed of perhaps.
It may also be that the code is not robust enough and was not developed to use a resilience library like Polly (funnily is there on the server).
Please don’t ask me about it… All I know it allows helps your apps work when things out of your control break, great for cloud environments. Here is a link https://www.pollydocs.org/