Conditional formatting changed from 2010 to latest?

I've got a rather large set of tabs using Conditional formatting, all created used with Excel 2010 (yes, I know, it's old)...when opened with the latest version (2016?) some of the formatting no longer works properly.  Is this a known issue?  Can it be from the shear number of formatting and conditions?

Thanks for any help!  I will probably move the development platform for next year, but I'd like to hold off this year in spending any capital for new gear, updated software, etc.