Gallup Poll has Trump at 49%.

[0rganism]

64. that disparity is handled by weighting the results to match general population

as they say,
"Samples are weighted to correct for unequal selection probability, non-response, and double coverage of landline and cell users in the two sampling frames. They are also weighted to match the national demographics of gender, age, race, Hispanic ethnicity, education, region, population density, and phone status (cell phone- only/landline only/both and cell phone mostly). Demographic weighting targets are based on the March 2019 Current Population Survey figures for the aged 18 and older U.S. population. Phone status targets are based on the July-December 2018 National Health Interview Survey. Population density targets are based on the 2010 census. All reported margins of sampling error include the computed design effects for weighting."

handling unequal and even unrepresentative sub-populations is standard operating procedure for professional pollsters.

the main effects of under-sampling Democrats will be increased inaccuracies in secondary calculations based on unions and intersections of Democratic responders relative to the Republican sample.

i highly recommend referencing an aggregation site like https://fivethirtyeight.com/ this poll could easily be an outlier, but not because their samples were uneven.