Without talking directly to development, there is no way to know for sure but I suspect this flag indicates that the Edge.exe process will manually invoke GC during times that it makes sense to do so. Like after a document is closed. The seApplicationGlobalEnableDotNet2GC and seApplicationGlobalEnableDotNet4GC global parameters were both introduced with the release of ST7 and are enabled by default.
For more information, you would likely need to submit an IR with GTAC to ask for more details.
To help you with the access violation issue that you mentioned, if you can provide a reproducable sample, I'd be happy to look at it.