okay, one more point.
Usually when we click on VS project inside AX and click EDIT.
it loads Project in Visual Studio and also loads a report also itself i.e. at this point you don't need to click solution explorer and open report by clicking edit. Till this point VS project is showing you report from temporary folder. it is not showing you report from AOT.
there could be two possibilities to load what's currently inside AOT exactly
1) Click your VS project inside AOT and click edit, now wait for project to be loaded. after project is loaded in VS. go to solution explorer and click your report inside solution explorer right click report and click open/edit
now do modification on this loaded report
OR
2) delete temporary project from folder physical from following path
C:\Users\YourUserName\AppData\Local\Temp\Microsoft Dynamics AX\Dynamics AX Model Projects
Delete your report project folder completely
now go to AOT and modify your report