Back from the dead? Philips TLD50W/84HF Electronic 5'

This one came to me in original sleeve and certainly looked new, but someone had written 'faulty' on it. Powered it up and sure enough, no worky. The cathodes were in tact and emitting fine (glowing white), but it refused to strike on HF gear that it's supposedly designed for. Anyway I left it on switch start with a glow bottle starter trying to start for about 5 minutes and eventually it struck but the majority of the tube was just a dull pink glow with the ends glowing bright white. After 15 minutes or so it'd come good and has been fine ever since.

Is this what you mean when you say a tube's contaminated? What causes this and is this tube toast or will it be ok now?