Why does a Powerpoint chart change to a different chart when linked to excel?

I have a ton of different charts linked to an excel workbook. Every once in a while (this problem comes and goes) I'll paste and link a chart into powerpoint. I'll then return to excel to grab another chart, then back to powerpoint. When I return to powerpoint my original chart mysteriously changes to a different chart on a different page on my powerpoint. It changes to a completely different style of chart with different data.

Any ideas on why this is happening and how to fix it?