We have evaluated the presented scenario while using the latest version of Aspose.Cells for Java 8.7.0.2, and we are able to notice the said problem, that is; the cells E5, E6 & E7 are being detected as of DateTime type. We have logged this incident as CELLSJAVA-41735 in our bug tracking system. Please spare us little time to properly analyze the problem cause and get back to you with updates in this regard.
It is to inform you that we have fixed your issue CELLSJAVA-41735 now. We will soon provide the fix after performing QA and including other enhancements and fixes.