Alexa not recognizing some slot values dependent on the sample utterances

I created an Amazon Alexa skill that has one intent (MyIntent) and two custom slot types (SlotA and SlotB). The intent schema looks like that:

{
  "intents": [
    {
      "intent": "Foo",
      "slots": [
        {
          "name": "CustomA",
          "type": "CUSTOM_A"
        },
        {
          "name": "CustomB",
          "type": "CUSTOM_B"
        }
      ]
    }
  ]
}

Each slot has a couple of values, like SlotA having

865985
710000
927291
514000

and SlotB having

Photo
Car
Bed
Kitchen

My sample utterances look like that:

MyIntent foo bar {SlotA}
MyIntent bar baz {SlotB}
MyIntent {SlotA}
MyIntent {SlotB}

The problem is, that Alexa doesn't recognize some of my slot values, like "bed", but does recognize others like "kitchen". This applies to both slot types.

The interesting thing is, that all values get recognized, if I keep only the simple sample utterances and remove the ones including phrases and my sample utterances look like that:

MyIntent {SlotA}
MyIntent {SlotB}

The order of the values or the sample utterances is irrelevant. I tried every combination. Also having two slots (combining all slot values in one) does not make any difference.

Why are the sample utterances with phrases blocking the recognition of some of the slot values?

EDIT:

By "doesn't recognize" I mean the user's input is not mapped to MyIntent. While being in a dialog (session) I just get a SessionEndedRequest.

Amazon had a bug in their system, preventing the language recognition from being build correctly. After the bug was removed, everything is fine again. Here is the email from the Amazon support:

We recently made new tools available to help with the creation and testing of skills. The new features inadvertently impacted a small number of skills. We fixed the issue yesterday and all live skills should work as expected. Please post here if you have any more issues and we will monitor and provide assistance. For skills in development, you can now resolve this issue by clicking ‘Save’ on the interaction model tab or by clicking Build Model in Skill Builder (beta). We apologize for the inconvenience.