Test flake: Catalog numbers should reject invalid values

[php-coder]

Test "Catalog numbers should reject invalid values" fails time to time with the following error:

Catalog numbers should reject invalid values :: Verify that fields... | FAIL |
You may only interact with visible elements
Build info: version: '2.53.1', revision: 'a36b8b1cd5757287168e54b817830adce9b0158d', time: '2016-06-30 19:26:09'
System info: host: 'testing-gce-ac45f61b-f89c-43b1-890e-12e8def8c2a1', ip: '127.0.1.1', os.name: 'Linux', os.arch: 'amd64', os.version: '3.13.0-103-generic', java.version: '1.8.0_111'
Driver info: driver.version: unknown

Log: https://travis-ci.org/php-coder/mystamps/jobs/210502209

[php-coder]

Seen here: https://travis-ci.org/php-coder/mystamps/jobs/211948655

[php-coder]

https://travis-ci.org/php-coder/mystamps/jobs/212472577

[php-coder]

Still here: https://travis-ci.org/php-coder/mystamps/jobs/213866713