airdrop between macbook pro late 2014 and iPhone 6

Since you are running a beta OS, the glitch could be related to that.

Well, you're using a Beta version of OS X. That's likely to be the cause. The guide specifically states:

Please note that since the public beta software has not yet been commercially released by Apple, it may contain errors or inaccuracies and may not function as well as commercially released software.

However, what you can do is report it to Apple using the Feedback assistant:

https://beta.apple.com/sp/betaprogram/submitting

One final note, you do realize that the Beta release of OS X is confidential? You really shouldn't be discussing it on a public forum:

Is the public beta software confidential?

Yes, the public beta software is Apple confidential information. Don’t install the public beta software on any systems you don't directly control or that you share with others. Don’t blog, post screen shots, tweet, or publicly post information about the public beta software, and don't discuss the public beta software with or demonstrate it to others who are not in the Apple Beta Software Program. If Apple has publicly disclosed technical information about the public beta software, it is no longer considered confidential.

Taken from here: https://beta.apple.com/sp/betaprogram/faq