This reminds me a lot of what happened just two years ago. Almost universally, Democrats were the ones publishing their House polls publicly. They went on to have a net gain of 40 seats in the House. Democrats also won the House popular vote by 9 points.

Indeed, the 2018 example speaks to a larger pattern going back since 2004. Although Democrats tend to publish more internal polls publically, they do very well when that advantage is overwhelming.

When Democrats put out 70% or more of the internal House polls, there is a big swing in their direction in terms of the popular vote. Since 2004, Republicans have never published 70% or more of the internal House polls. The only time there was anything close to this on the their (2010), they picked up more House seats than in any election in the last 70 years.

When Democrats put out around 60% of the internal House polls, the national environment is usually fairly unchanged from the prior election.