In a tweet posted on the official Sonic Twitter account, we've now learned what was likely the case: Sega is ending their partnership with Archie.

If the text is too small, here it is again:

After 24 years of memorable storytelling, SEGA of America will conclude their Sonic the Hedgehog publishing partnership program with Archie Comics. This does not mark the end of Sonic in comics, but signifies SEGA of America's decision to take a different direction for the series that will be announced at a later date. SEGA would like to thank Sonic's amazing fans for their loyalty and passion over all the years. SEGA looks forward to providing more information soon.

While this isn't really surprising, it's still shocking as it's been a long 24 years. Hopefully we'll learn the future of Sonic comics very soon. I have a feeling they wanted these two announcements to be very close together.