fix(xo-server): don't use stats that were cached exactly one step ago

[b-Nollet]

Description

Update stats instead of using cache when cache is exactly one step old. It avoids the stats to be twice the same in a row when fetching it every step.

Introduced by 8347ac6ed8359c489b22181bc43da2612b8b03fb

Checklist

• Commit
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