It shows you addition results which could have 4 digits as it's just addition math.
But the Pick-3 results and the Combos shouldn't give you any 4 digits one as I take the last 3 digits only...unless there's a bug but I don't see a bug in code...unless you can share your input examples or screenshot.
Addition results: 249 231 339 330 150 141 250 241 340 251 341 350 252 261 342 360 450 441 253 271 343 370 550 541 254 281 344 380 650 641 255 291 345 390 750 741 256 301 346 400 841 850 257 311 347 410 950 941 258 321 348 420 1050 1041
Pick3s from results: 249 231 339 330 150 141 250 241 340 251 341 350 252 261 342 360 450 441 253 271 343 370 550 541 254 281 344 380 650 641 255 291 345 390 750 741 256 301 346 400 841 850 257 311 347 410 950 941 258 321 348 420 050 041
Pick3s combos from above: 004 005 013 014 015 024 025 033 034 035 036 037 038 039 045 055 056 057 058 059 113 114 123 124 125 126 127 128 129 134 144 145 146 147 148 149 225 234 235 245 249 255 256 257 258 334 339 344 345 346 347 348
Pick3s sorted combos:004 005 013 014 015 024 025 033 034 035 036 037 038 039 045 055 056 057 058 059 113 114 123 124 125 126 127 128 129 134 144 145 146 147 148 149 225 234 235 245 249 255 256 257 258 334 339 344 345 346 347 348
Addition results: are the math done by just adding numbers you said with carry so regular math can produce 4 digits
PIck3s from results: will only grab that last 3 digits from Addition results
Pick3s combos: are unique combos from Pick3s result so it gives you only uniques (for example if 302 and 320 are in Pick3s from results) this will only give you 023.
PIck3s sorted combos are just the Pick3s combos above sorted in ascending order.
Note: the last shared link has all of these groups listed. since someone asked for unique combos and then I thought what if they wanted sorted (and that's why there are many links shared).