Period date moved

Cara
I was due to get my period today. I have a pretty steady 25 day cycle and Glow (and the webmd <a href="https://play.google.com/store/apps/details?id=com.glow.android">ovulation calculator</a> that I used before I discovered Glow) has predicted my AF date very precisely on a month to month basis. 
I did not get my period today. I deleted the period from the Glow <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period calendar</a> for today. However, now when I look at both my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period calendar</a> and my cycle graph, it shows that my period is now due 9/3 and my usually-normal cycle of 25 days has jumped to 32 for this month! Is this normal, or a glitch in the app? Has anyone ever experienced this?