Trust the pattern more than the promise made after you noticed it.

Behaviour observed over time is data; a promise made immediately after being caught is a response to being caught. It is produced under pressure, aimed at restoring the situation, and it costs nothing to say. That does not mean it is insincere, only that it carries almost no predictive weight compared to what has already been repeated. The pattern was collected without anyone performing.

When someone assures you after you have raised something, note it and then keep watching. Give the following months more weight than the conversation. Patterns change slowly and visibly, or they do not change.