No, it is not.
Actually, 18 percent undecided is the highest number in the Morning Consult poll this season. Notice that Trump never goes higher than 42% in any poll but that very questionable LA Times poll (which is an outlier as it is the only one showing Trump with a lead).
Meanwhile, in an effort to facilitate party unity in Arizona, Trump has been on a rampage against Jeff Flake, who is very popular:
Donald J. TrumpVerified account
@realDonaldTrump
The Great State of Arizona, where I just had a massive rally (amazing people), has a very weak and ineffective Senator, Jeff Flake. Sad!
Donald J. TrumpVerified account
@realDonaldTrump
The Republican Party needs strong and committed leaders, not weak people such as @JeffFlake, if it is going to stop illegal immigration.
Stephen MillerVerified account
@redsteeze
Ground game, data op, campaign offices - ❌
Tweeting about things he sees on TV that make him mad? MAGA - ✔️