When using the selector tags, both in the chat and in the command block, it tells me I have formatted the tags wrongly, although I've double checked it, and I've tried the exact command in previous versions of Minecraft.
I've experienced this many times in the newer snapshots, but I've only experienced it with the scoreboard tags (yet).

Also the selector won't operate with numbers equals og is lower than 0.

The weirdest thing is, it does not fail every time. If I changes the order of the tags, or replace the commandblock, it sometimes work afterwards with the exact same command.

Example:

/testfor @p[score_tag1_min=1,score_tag1=1,score_tag2_min=9]

What I expected to happen was...:
I expected to run a testfor command successfully, formatted correctly.

What actually happened was...:
It get a red error code, telling me I have formatted the UUID is provided in an invalid format. (It works in previous versions)

Steps to Reproduce:
1. Put down a command block or open the chat
2. Enter a /testfor command with scoreboard selector tags.
3. Run it

(Just before I sent this, I experienced it with coordinates too)