Depth finder stuck at 1.5ft

[gschafer]

I have a 2019 R7 and recently moved to Lake Tahoe. When boating into areas of the lake that are greater than 1,000 feet, my depth finder gets confused and reports a depth of 1.5 ft. It then stays like this until I'm in shallower water for 10-15 minutes. Any ideas on what is going on?