In placement files shapeType uses "__" intead of '-' char for declaring a differenciator. The point is second one is used only in template files as can be seen in documentation http://docs.orchardproject.net/Documentation/Accessing-and-rendering-shapes#NamingShapesandTemplates
However GetShapeType looks for '-' character ignoring placements for a ShapeType with a differentiator. This produces strange behaviors and a lot of headaches to users because when they set for example: <Place Fields_Common_Text__SeoTitle="/Header:0"/> in a placement file it forces all Fields_Common_Text shapes within the same Match to be rendered at Header:0 area instead of only affecting those with the SeoTitle differentiator.
Image cache is empty after every reboot of the Orchard app. It makey Dynamic ImageProfiles reprocess images after every reboot. It has a big impact on performance because all the images that use dynamic profiles are reprocessed when they are requested after a reboot. When you open a page with a number of images disks usage increases drammatically and the apps answer very slow to other requests
This is related with this issue https://github.com/OrchardCMS/Orchard/issues/5061