Printer makers have long used chips to thwart third-party ink cartridge sales and drive you toward their own products, but they’re now feeling the sting of those restrictions. The Register and USA Today note Canon has had to ship toner cartridges without copy protection chips due to ongoing shortages. That, in turn, has led to some ImageRunner multifunction printers incorrectly flagging official cartridges as knockoffs — Canon has even told printer owners how to bypass the warnings and deal with broken toner level detection.

We’ve asked Canon for comment. Some users said they’ve encountered similar issues with HP printers, but that company wouldn’t directly confirm or deny the problems in a statement to The Register. Instead, HP said it was using a “globally diverse” supply network to stay “agile and adaptable” in the midst of chip shortages.

The printer trouble illustrates one of the common complaints about digital rights management (DRM) and other copy protection systems: they create trouble the moment their designers can’t offer full support. Just ask people who bought music tied to Microsoft’s PlaysForSure, for example. It’s doubtful Canon, HP or others will drop their DRM chips any time soon, but this incident won’t exactly help their case.

Update 1/12 1:05PM ET: Canon told Engadget its focus was to “limit possible disruption” to customers, and that included shipping toner cartridges without the anti-knockoff chips. The company stressed there was no shortage of the cartridges themselves — American customers still had a “continuous supply.” You can read the full statement below.

While the global shortage of semiconductor components continues to affect many industries, it’s our priority to limit possible disruption to our customers. As with all manufacturers, we continually monitor our supply chain to anticipate and prepare for any potential disruption and we are taking steps to deal with the situation, such as adjusting product designs. One example of this is in toner cartridges for some of our MFP devices (imageRUNNER/imageRUNNER ADVANCE) as we are currently facing a shortage of the chip that is fitted inside the toner cartridge to monitor its remaining toner levels. There is no shortage of toner cartridge itself – a shortage of the chip that lies inside the toner cartridge. As such, we’re now shipping toner cartridges for some of our MFP devices without this chip to ensure we’re still providing a continuous supply of consumables to our Canon U.S.A. customers. We have also issued guidance on how to install and manage these new toner cartridges.