Updated 5/25/2018 — Shortly after this news broke, Huawei reached out to Android Central with an official response. The statement is almost identical to the one found in the pop-up on the company's unlocker site, with the addition of citing "system failure, stuttering, worsened battery performance, and risk of data being compromised" as the risks involved with ROM flashing and the ultimate reason this decision was made.
If you're big into the Android modding community, chances are you've taken a liking to Huawei. Huawei's gradually become one of the more developer-friendly companies in the Android space, but that's all changing.
According to a pop-up found on the company's unlock page:
To provide better user experience and avoid issues caused by ROM flashing, the unlock code application service will be stopped for all products launched after 2018-5-24. For products released prior to this date, the service will be stopped 60 days after this announcement. Thank you for your understanding. We will continue to provide you with quality services.
In case you don't know, unlock codes are required for phones to perform deeper system modifications, such as installing a custom recovery like TWRP, flashing custom ROMS, gaining root access, etc. In addition to Huawei phones, this change holds true for Honor ones, too.
This obviously isn't something that'll affect the majority of users, but for those that like digging into Android's more technical side of things, this is disappointing news, to say the least.