what filter did you use?, i know of cases where filter media came off and clog oil lanes, causing low pressure
Firestone did the oil change and filter - the issue started about 70miles after the oil change. I towed the car in and they did the oil/filter again - and they showed me it is still doing irrespective of how much engine oil is on the dipstick. Firestone advised me to take it to Honda technicians for the flickering issue.
Since the 2nd oil change, 2nd or 3rd time I drove, the issue had stopped - then it came back once as per my most recent post - this time it was bright red but flickering - went off when I turned off the engine.