For clarification, do you have the SL or the SL 2.4?
I have the SL and don't believe that it has a "find" feature, while it searches for the HR signal. That sounds to me like the SL 2.4, which is a coded HR signal and requires the CPU to "learn" the HR code, as well as the hub and cadence (if option is used).
BTW, it is not uncommon to get HR drops when riding with other's while using the SL (non-coded) HR set-up. The new SL 2.4 uses the coded, which should eliminate that issue.
I think that some of the responses you are receiving are mixing the instructions of the two units.