Strictly speaking, many of the issues listed here are not really issues of the Flower app per se, but issues of particular devices and their particular installed software. Every year, both the software that runs our devices and the devices themselves become more mature, so over time we expect issues with our apps to become fewer. Unless you have an older device, with the exception of the entry on side-swipes, most of the issues listed here are rarely seen these days.
If your device is running low on internal storage or other system resources, you may need to do a device restart to get the app to work properly.
This is a general problem with large apps, and is most likely to be seen the first time you try to run an app after installing it. There is more on this type of issue on Apple's support web site. To find their discussion you can try searching on If an app on your iPhone or iPad stops responding, closes unexpectedly, or won't open
The 'Settings' app may need to be restarted before the settings of a recently updated app may show.
This is referring to the device's main 'Settings' app (that is, the gear icon on the device's Home screen.) Completely closing the Settings app should fix this. That is, double-tap your device's home button and then swipe the Settings app up off the screen. The issue should be resolved when you reopen the Settings app. Obviously, doing the more drastic Device Restart would also fix this.
Back and Forward side-swipes will not work if the view is zoomed.
Please note that pages may well be zoomed a bit after you change the screen magnification by adjusting the Page Zoom, the Device Size, or the Text Size. This can also happen after a page rotation. Pinching back to an un-zoomed state should fix things. The issue here is that if the screen is zoomed, even a little bit, the device has no way of knowing if a 'swipe' should be interpreted as a pan or a true swipe. Currently, the default behavior of the Operating System is, when in doubt, assume the user wants to pan.
This is also a problem specifically associated some combinations of the above screen magnifications. If the total magnification you have chosen goes beyond the original design of the page so that the page layout becomes distorted, your device may take it upon itself to make things look 'nice' for you by zooming the page, and this may prevent swiping. As mentioned above, pinching the distorted page to an unzoomed state should remedy this. This situation can also occur if you use the 'Tablet' setting with a Phone device, especially for the 'Small' page zoom and/or the 'Small' text size (another unlikely magnification extreme, but this time making things look tiny). In some cases it may not be possible to pinch to undo the zoom. In this situation, you can always use the 'Back' button on the toolbar to go back, or the double-tap of the Back button to go forward. BTW, don't forget about double-tapping objects on the page to quickly zoom in or zoom out. In particular, double-tapping a blank part of the page should zoom all the way out.
Similarly, swipes will not work if there is any vertical movement of the page (that is, the screen is still scrolling). Generally speaking, nothing can happen while the screen is scrolling.
Cannot pinch a zoomed page back to an un-zoomed state.
As mentioned above, the 'Small' page zoom, or other combinations of settings that make things look tiny, may result in a situation where you cannot pinch to completely undo a page zoom. The most annoying thing about this is when the page is zoomed you cannot use swipes to navigate back or forward. In this situation, you can always use the 'Back' button on the toolbar to go back, or the double-tap of the Back button to go forward. Or, of course, if you have one of the affected devices, you could avoid using settings that lead to things looking tiny.
Any change of scale (that is, the page magnification) by changing the settings 'Page Zoom', 'Device Size', or 'Text Size', may cause a loss of the page position.
In general, the app's ability to return you to your last position on a page when going back or forward is dependent on many factors. In particular, when you adjust any one of the three magnification settings (Device Size, Text Size, and Page Zoom) the previously saved page positions will probably no longer apply to the new view. Once you find your preferred settings for the app and stop adjusting them the page positions should become reliable.