I think they’re both data weaseling but of different severities.
Leaving the precise definition of a goal unspecified leads to wiggle room. Ideally every goal would have a fully specified, precise definition of what counts and what doesn’t. Then, changing that precise definition should be subject to the akrasia horizon just like any other adjustment to your commitment. If you’re editing the definition of your goal inside the akrasia horizon, you’re data weaseling.
In reality, a lot of goals have corner cases that are hard to think of in advance. Consider the discussion at Advice for goals which have external dependencies . It’s impossible to pre-enumerate all possible issues. But I wouldn’t call that “weaseling” unless that definition shifts around a lot or is applied inconsistently.