Statistic is not correct

Hi, we have experienced incorrect open stats lately. The usual open rate of our newsletters are around 20-40% but the last newsletter just sent out a few days ago has an open rate of 91.7%. We didn’t notice this first.

We first noticed that the bounced email addresses have been marked opened when viewing the subscribers. The emails were bounced so they should not be marked open.

The open rate is also not 100%, otherwise I would think that the mail server software checking links could be possible, like what was describe here.

Can you please advise where to start checking? Thanks.

https://www.ads-software.com/plugins/wysija-newsletters/