I just noticed that my charger is flashing blue/red lights simultaneously. In the past they have stayed on continuously until fully charged at which time the red went away and the green came on. I have read thru my manual and can't find my answer. Does anyone have clue what my have caused this?

Bad battery or bad connection? When mine flash, it's indicating a bad battery or connection. Mine is a DualPro 3bank 15 amp. Not the same as yours...but maybe similar.

Do you have blue/red LEDs for multiple banks, and are all blinking or just one set? Often, such blinking means a safety fault such as a battery discharged below 10.5 volts. Most smart chargers won't recognize or charge such a battery. This may mean you have a battery that's basically ready for a recycle.

If you have a voltmeter, and multiple banks, check the charging voltage of each battery. A good battery being charged should read over 13 volts, typically ~13.5V. If you have one bank that's a lot lower, you can unplug, switch the charger leads between batteries as pairs, then plug it in and meter again. If the low voltage still reads on the same battery, the battery is bad. if the low voltage moves to the other battery, the charger output is bad.