To expand upon the correct answer, this has been an going issue with the Legacy lineage. I have seen in logs how the ECU for my '05 takes a couple seconds to finally determine/update its correct gear based on rpm vs mph, or in the case of the automatics it's trans input shaft speed sensor vs output shaft sensor or abs sensors. Apparently the Reverse switch in the MT is not just hooked up to the light switch, but instead to the BIU.
Radically improve 05-07 5EAT shifting and power limits with the
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