With latest version of Chrome 87.0.4280.141 is not possible to download pdf file via inotes Full mode on Android devices. If you change to ultra-light mode or enable the desktop option you can download pdf files normally. You can reproduce the same problem with Microsoft Edge 184.108.40.20621. If you use Firefox or Opera can download normally pdf attachemnts. For other extensions as jpeg, docx, etc does not happen the problem.
Please your help to fix this problem in the next versions and avoid all browsers start to block attachment download.