It's a normal part of scaling because often bringing in the new technology introduces its own ways of causing the exact same problems. Often they're difficult to integrate into automated tests so folks mock them out, leading to issues. Or a configuration difference between prod/local introduces a problem.

Your DB on the other hand is usually a well-understood part of your system, and while scaling issues like that can cause problems, they're often fairly easy to predict- just unfortunate on timing. This means that while they'll disrupt, they're usually solved quickly, which you can't always say for additional systems.