Line + Stacked visualisation broken after update?

I've got a strange issue which, although it may be coincidental, seems to have only started happening since the last update.

I've got a Line + Stacked chart combo that shows lifetime data since March 2015 comprised of two column values and two line values. However now I can rarely get it to show all the data, it stops at 19th June and only shows one column value and one line value. There are no date filters on the page or the visual, and sometimes I can get the full timeline of data if I create the same visualisations but just with the column values but adding line values breaks it again and removing those line values doesn't fix it, I have to delete the visualisation and sometimes that still doesn't work. Interestingly though, if I use the 'Export Data' option all the source data is there!

Also to reiterate that it's not the dataset (they're all from one table). If I put the values separately in a line visualisation or a stacked chart visualisation they display correctly.

As I said, this was working before, so I'm inclined to think this a bug with the 31st May update, but if anyone has any other ideas?