Adding assets to new buckets problem with 3.0.9

I've updated a Perch installation from 3.0.8 to 3.0.9 and noticed that when I add a new bucket via a template (i.e. <perch:content type="image" id="image" label="Image" width="500" quality="70" bucket="bios" />) I'm not able to upload assets. The asset dialog opens, I click 'add asset', but when I try to drag/drop an image or click to select it through the OS file manager, nothing happens. Debug shows no errors, but I don't believe the debug log updates to show errors from the asset dialog, does it?

I'm not using buckets.php to declare buckets, and I never have. I've always just added buckets by adding bucket="" to the template. According to the doc at https://docs.grabaperch.com/perch/resources/buckets/, that shouldn't be an issue.

Diagnostics:

Perch: 3.0.9, PHP: 5.6.24, MySQL: mysqlnd 5.0.11-dev - 20120503 - $Id: 76b08b24596e12d4553bd41fc93cccd5bac2fe7a $, with PDO
Server OS: Linux, litespeed
Installed apps: content (3.0.9), assets (3.0.9), categories (3.0.9)
App runtimes: <?php $apps_list = [ ];
PERCH_LOGINPATH: /cca-admin
PERCH_PATH: /home/mttstage/calvaryca.staging.mytechtailor.com/cca-admin
PERCH_CORE: /home/mttstage/calvaryca.staging.mytechtailor.com/cca-admin/core
PERCH_RESFILEPATH: /home/mttstage/calvaryca.staging.mytechtailor.com/cca-admin/resources
Image manipulation: GD
PHP limits: Max upload 64M, Max POST 64M, Memory: 128M, Total max file upload: 64M
F1: 3b606135b33e6a102526838f4152a807
Resource folder writeable: Yes
HTTP_HOST: calvaryca.staging.mytechtailor.com
DOCUMENT_ROOT: /home/mttstage/calvaryca.staging.mytechtailor.com
REQUEST_URI: /cca-admin/core/settings/diagnostics/
SCRIPT_NAME: /cca-admin/core/settings/diagnostics/index.php