Electrical – Why electrical switches are rated lower for led than incadescent lights

As I don't know the interns of this dimmer it might switch when the alternating voltage (and therefore the current with resistive loads) crosses zero. To detect the phase (crossing 0V will occur at 0° 180° and 360° which is again 0° - you might want to look it up here: http://en.wikipedia.org/wiki/Phase_(waves) ) and the type of load (e.g. inductive loads delay the flow of current depending on their inductance and the frequency in relation to the voltage. I could not find a text on wikipedia describing that so here's a plain image: http://people.sinclair.edu/nickreeder/eet155/PageArt/phaseInductor.gif

To detect the type of load it has to observe the mains line for a short period of time without regulating it.

The issue does not occur on light loads because most dimmers can handle inductive, capacitive and resistive loads quite well on low power levels.

By letting the dimmer "cool down" you may erase its short term memory so it has to resynchronize every time you switch it on.

Again: As the internals of this dimmer (or better: the two) are not known I can't provide a better answer. A newer hardware revision usually improves the product. Also chinese manufacturers tend to produce lower quality products as seen here: http://hackaday.com/2012/08/15/buying-cheaper-electronics-and-not-saving-money/

Dimmers have to be compatible with the types of lights in use. The bog standard dimmers that have been in use for years generally work fine for incandescent type bulbs and the halogens that work at direct line voltage.

With the advent of CFLs (compact florescent lamps), low voltage halogens and LED types it talks special types of dimmers for these to be used in a variable brightness mode. Do note that not all items are even dimmable and you can get into serious overheating issues in either the dimmer switch or in the light module if you try to operate with a dimmer. Similar issues can happen when a non-compatible type of dimmer is in use.

My suggestion for you, if you need to keep the mix of light source types, is to convert over to simply using a switched on-off control instead of dimming. If dimming is desired then switch all of the light sources on the circuit to the same type and then select a dimmer that is compatible with that type of lamp. Modern dimmers should show on their box what types of lamps they should work with. In the realm of the light sources themselves you may need to do some additional research to determine if a particular low voltage halogen, CFL or LED lamp assembly is actually dimmable. It may come down to specifically only purchasing items that are marked as dimmable on the box or product information sheet.