countdown app's notifications don't work when less than 1 minute is set

[YougoCodes]

• Device: FP2
• Channel: devel
• Build: 15.04 r106

Steps to reproduce

1. install apps with countdown function e.g. Timer or Stopwatch from the Open Store
   https://open.uappexplorer.com/app/stopwatch.mzanetti
   https://open.uappexplorer.com/app/timerpro.mivoligo
2. start an app
3. set time less than one minute
4. start the countdown

Expected behavior

• countdown starts counting down, when reaching t=0 a notification appears.
• countdown continues counting down even when other app is selected or device is locked
• notification will happen at t=0 even when other app is selected or device is locked

Actual behavior

behavior is erratic, but a trend is shown:

• most often the notification happens immediately after countdown is started
• if one switches to another app or locks the phone quick enough, notification may or may not come at t=0
• if one starts the app, switches away and back, and then sets and starts the countdown, notification may or may not come at t=0.
• in all cases after premature notification, the countdown continues, but no notification comes at t=0
• in all cases when t>1 minute is set, countdown and notification work properly

Logfiles and additional information

• I am willing to provide logs, but don't know how or which ones. guidance is appreciated. I am confident at the CLI.
• Timer's app description on https://open.uappexplorer.com/app/timerpro.mivoligo mentions the following:

IMPORTANT!
Please notice that the app depends on the Alarm API which has some limitations. There are few things you need to know:

1. Notifications for timers shorten than about a minute are not displayed at the right time.

[Flohack74]

Hi,

currently we are limited by the Android alarm API which does not allow to set alarms shorter than 1 minute, if I remember right. I flag this as opinion therefore, since we must make up our mind in which way to go with this.