Tax free shopping on working holiday visa

Am I eligible for tax-free shopping if I am here for under 6 months, on a working holiday visa, and currently working in Japan?

I'm getting different answers from all over the place. Some stores have told me that I am not and others have said that I can. Even after Googling, some sites say I can't if I'm working and others say it's fine as long as I leave within 6 months. Maybe a change in the law/rules has been made recently?

My friend, who is also on a WHV, ended up buying a tax free item at a store that thought it was allowed and stamped his passport. What will happen at customs if it turns out that he's not eligible for the tax-free item? Will he just need to pay the 8% or will there be an additional fine for trying to do this?

Tax free is only available for temporary visitor visa for stay up to 90 days, or if you extend for further days for certain countries.