This is normal behavior.

You could adapt your workflow in development to

1. delete the fields from view
2. push and upgrade the module
3. delete the fields from model
4. push and upgrade the module

However, when using version numbering correctly in your module, even committing all changes at once should work just fine.
In this scenario this would also make sense, since 1) would be a minor release (if committed individually), still backwards compatible from the model's perspective (i.e 18.0.x.0.1), and 3) would then be a db table modification with, usually, greater impact (i.e 18.0.x.1.0).

See also the output on odoo.sh Shell for odoo-update:

cfarnleitner-xyz [staging/18.0]:~$ odoo-update -h
Update Odoo module

This script proceed to a manual update of one or more Odoo modules in the database.

NOTE: this command is handy to quickly test updates during some development iterations,
      however keep in mind that on Odoo.sh the convention is to increase a module's
      version number in it's manifest file whenever the committed changes requires
      a database upgrade. Please refer to the documentation for more details:
      https://www.odoo.sh/doc/getting_started/branches.html#production


Usage:
  odoo-update [--help] <module>

Options:
  -h, --help           Show this screen and exit.
  <module>             Module list to update separated by comma.
                       Use 'all' as module name to update all modules at once.

In addition, in odoo.sh you may navigate to the Builds menu. Here you should be able to access recent, failed instances as well: