Voice dictation repeats whole sentences in a big garbled chunk on Mac OS X High Sierra

Problem:
During macOS dictation, it sometimes repeat-types the sentence I have spoken multiple times in a row. This seems to happen randomly. Sometimes every minute or two, sometimes taking up to 20 minutes between occurrences.

Example:

1. I said: I’m using Mac OS 10 dictation for this, and I’m very
   impressed with the quality period I had to fiddle with the settings to get it to work right at first period
2. The computer immediately output an entire paragraph of garbled repeats of those sentences. See the results below:

I’m using Mac OS 10 dictation for this, and I’m very impressed with the quality. I hdI’m very impressed with the quality. and iI’m very impressed with the quality. Ifor ovI’m very impressed with the quality. I hfor ovI’m very impressed with the quality. I had to fiddle with thi setting tI’m very impressed with the quality. I had to fiddle with the settings to get to wtI’m very impressed with the quality. I had to fiddle with the settings to get to wortI’m very impressed with the quality. I had to fiddle with the settings to get to work tI’m very impressed with the quality. I had to fiddle with the settings to get to work ritI’m very impressed with the quality. I had to fiddle with the settings to get to work rightI’m very impressed with the quality. I had to fiddle with the settings to get to work righI’m very impressed with the quality. I had to fiddle with the settings to get to work rhI’m very impressed with the quality. I had to fiddle with the settings to get to workhI’m very impressed with the quality. I had to fiddle with the settings to get ito work rI’m very impressed with the quality. I had to fiddle with the settings to get it to work r I’m very impressed with the quality. I had to fiddle with the settings to get it to work right at first.

Troubleshooting so far:

• Quit all other apps that might be using the microphone
• Turned off advanced dictation commands
• turned dictation on and off
• Turned off "Enabled dictation keyword phrase"
• Turned off "paste that" and "Copy that" dictation commands
• Searched the web for others with this problem
• Searched Ask Different for this problem in the past
• Searched apple support site for dictation support articles (they have deleted all High Sierra support articles)

I’m using Mac OS X High Sierra 10.13.6, Enhanced Dictation is on, Language is English (United States) on a MacBook Pro 15" Retina mid-2015. Application is Day One Journal. I just turned on dictation and this immediately started happening.

Thank you!

P.S. With great irony, I thought the problem was solved after 20 minutes of it not happening, and I tried to tell my journal I was happy about solving it. That really is the single sentence I tried to dictate, and it immediately spewed all that out.