For now I can`t give a time frame on when the issue with the precompilation of razor template that results in high CPU utilization at site startup will be resolved, at the moment we are working on a fix that is to precompile the razor templates into separate assembly, this will resolve the templates without compilation at startup.
For the scenario where one of the sites doesn`t encounter performance hit: The precompilation occurs at every site restart, for the next release those templates will be served precompiled form assembly. I don`t see any reason that the precompilation will be skipped for one site as there is no such option implemented.
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