Libreoffice
Version: 4.2.8.2
Build ID: 420m0(Build:2)
I am running Ubuntu 14.04.5 LTS with all the latest updates. I have a number of Libreoffice presentation documents (.odp) with equations in them. I have used and edited these documents for the last year without any problem. Today, every time I double click on an equation and go to edit it, upon leaving equation mode the equation becomes invisible. I don't even have to modify the equation for this to happen and the equations are invisible in both editing and full-screen presentation mode. If I save my document, restart my machine and reopen my document, the equations are still invisible. The equation objects are there - I can select the region with the equation and even open up the math editor to see that the equation code is definitely present, but I have found no way to make them appear outside of the math editor.
I am attaching a number of screenshots and a test document demonstrating the problem.
I should note that the problem does not occur with a brand new presentation. With a new presentation, I can add and edit equations without any problem. I am attaching two presentations in .fodp format (flat XML). The two are different even though there shouldn't be any differences (same master sheet, same content), but the differences are too complex for me to spot a smoking gun. I will say that the binary data of the equation itself looks to be the same between the two.