Link to the top generates error

Squiz Matrix Support
1

I've got the following code:

    
top of page arrowtop of page


Which seem to generate the following error (sent by email):
    [ASSERT EXCEPTION] [string] "7100d5fd1f83" is not a valid asset ID (LINE 843 IN [SYSTEM ROOT]/core/include/asset_manager.inc) [SYS0270]


Note that I'm getting multiple errors and the string appended to the asset id (i.e. 'd5fd1f83') is not always the same.

Is this a bug?
Why is it that not all anchor links are affected by it? Is it due to the image?

Edited: to improve the wording and to add: v3.8.0RC1.