Bulk Action Bug - unable to save action to update Asset Type

Wonder if anyone has the problem:

I need to set a list of asset to a new Asset Type which I have just created.

For example, currently I have Monitor 17", Monitor 19" etc etc... as asset type. I have decided to consolidate all of them and just call it Monitor. And will use another custom field to state the size)

So what I have done is to create a Bulk Action, let's set the name as "Set Monitor Asset Type", so all it does it set the Asset Type to " Monitor".

When I run the action, it seems running okay - BUT nothing has been changed.

So I look more closely by running it again, and realise the pop up message box (after you click on the play button) say the following:

Perform Bulk Action "Set Monitor Asset Type" on these 30 items?

The following changes will be made:

[No Changes]

(To abort, edit or delete this Bulk Action, click Cancel)

So I naturally assume the bulk action was not saved correctly, and I was right. The Asset type drop down is empty. So I edit and save it again... only realize it is doing the same thing.

So in short, I have NO WAY to save my bulk action to change "Asset Type".

Funny enough I have no problem to create bulk action to change custom fields (although I will need to logout, log back in to see the changes)

I am hoping someone will be able to shed some lights on how to get it done. Thanks.