Some Pokemon are Transforming into Another Pokemon Without Warning, Might be a Bug

We have a situation in Pokemon Go where some Pokemon are changing from one species to another during the 30 minute “spawn window”.
The players thought that this change was because of the “weather spawns” and the change of the species of the Pokemon was due to the weather change. But, it seems like the weather feature is not the cause of this issue and not everyone has this “bug.” Here is what happens as reported on TSR on Reddit:
- Slakoth > Spoink
- Unown > Zigzagoon
- Slakoth > Gulpin
Both common and uncommon Pokemon are affected by the changes. Pokemon like Ralts, Unown, Slakoth, and Venonat suddenly transforming into another Pokemon without warning. Half of the players think that this is the way Niantic is fighting back against the trackers, but this change became bigger and bigger, affecting many Pokemon. It would be quite frustrating to see an Unown on the screen, only for it to become a Zigzagoon before you are able to catch it.
We do not have an official statement about these unusual transformations, but we think that this is a bug. We just hope it would get fixed before all of the players become affected.