iOS memory usage increasing, can't find the culprit
According to the memory monitor in Xcode, this is causing unbounded memory growth (and eventually memory warnings and force quits) - but profiling the memory usage using the allocations instrument shows the memory usage to be stable.
Believe Instruments and the Allocations information - not the memory monitor in Xcode. The memory monitor graph is completely irrelevant. Ignore it.
This is not because the memory monitor in Xcode is useless or wrong. It is because memory management is completely different for a debug build than for a release build (Instruments uses a release build). This is especially true in Swift (you don't say whether you're using Swift).
Observe memory usage only on the device and only in a release build. Otherwise, you'll be completely misled.