The IRS is running just a wee bit behind this year so the fact that your client hasn't received a refund yet on an amended return isn't surprising.
What were the amounts and/or issues on the two that received quick refunds? My experience with paper-filed amended returns has been that they are either paid very quickly, like within four weeks, or very slowly, like 14 to 26 weeks. They won't tell us the criteria for a second look, but it probably involves amounts below a certain figure, and simple issues like an additional W-2 or mortgage interest deduction.
Faster refunds on e-filed original returns ≠ fast refunds on e-filed amended returns
I think a lot of people confuse electronic filing with actual processing of returns. A return having been e-filed doesn't necessarily equate to the IRS processing the return; it just means that data has been entered into the IRS' system but the processing itself may take some time depending, in part, on whether the IRS will review the return in more details.
Still an AllStar
@itonewbie "I think a lot of people confuse electronic filing with actual processing of returns"
What confuses people is that original returns are not reviewed by IRS for tax issues -- they are not "examined." With paper returns, one clerk looks at them to make sure they are in an acceptable format, and then a keypunch clerk enters the data. With electronic returns, the software performs both functions. Neither the clerks, nor the software, look for audit issues. E-filed amended returns, however, must still pass a smell test. If the OP wants to tell us the issue and amount involved in his/her return, it might illustrate how the system works.
Does it say the return has been received? My client got the message that they were working on it and to call if he did not hear anything further after 14 weeks. He called after 14 weeks and a nasty IRS clerk told him it hadn't been 14 weeks, and there was nothing she could do about it. He called back a month later, I haven't heard the outcome of that call. (The issue is IRS error in processing a solar credit carryover.) If the IRS website doesn't say they have the return, I think it's "lost in mail" time to start over.