VLOOKUP to return multiple unique results in a single cell

I've got Table 1 with tracking numbers. I've got Table 2 with tracking numbers and invoice numbers. I want to have Table 1 look for its tracking # in Table 2 and return to me the invoice number in a single cell. (Sometimes there will be a single tracking number that appears on 3 different invoices and I want all invoice numbers to appear in the same cell.) I've found a formula that will pull all results in a single cell. BUT . . . it's returning every single time that tracking number appears on that invoice which could be upwards of 15 times. I want a formula that will return multiple UNIQUE results into one cell. Any ideas?

This is the formula I'm currently using: =TEXTJOIN(", ",TRUE,IF(G:G=E1,I:I,""))

How do I tweak that to return just unique values in a single cell and not all values?

(This formula is slightly altered from how it is actually displayed in my spreadsheet. I keep getting an error here telling me I can't post links, images or videos since I'm a relatively new user. I don't know what it is about that formula that is triggering the error.)