Polygon Returning Incorrect Result

For this test case polygon() seems to return an incorrect result:

// Bounding box var bbp = [-123.5006568260586, -268.5301901840667, -113.19703085688374, -261.59299895444263]; // Test polygon var poly = [ [-127.7861230010377, -316.24149777631044], [-116.70896693414316, -294.6055724833417], [-112.85776301568613, -270.41743161420106], [-108.94104548638926, -246.3102843974042], [-113.9284569854127, -222.40054013470888], [-100.48054530104075, -224.3864178730988], [-95.49313380201731, -248.2961621357941], [-99.40985133131419, -272.40330935259095], [-103.26105524977122, -296.5914502217316], [-114.33821131666575, -318.2273755147003] ]; let t1 = lineclip.polyclip(poly, bb); // t1 = [[-113.19703085688374, -268.5301901840667], [-113.19703085688374, -261.59299895444263], [-113.19703085688374, -261.59299895444263], [-113.19703085688374, -268.5301901840667]];
Note that the x coordinate of the intersection box is exactly xmax. It looks to me like the polygon hits the bounding box in exactly the upper right corner. I think that case should return no intersection or just the point intersection, but what actually gets returned is the entire right side of the bounding box.

Start by reproducing the supplied polygon and bounding-box case through lineclip.polyclip, using the coordinates in the issue. Compare the returned right edge with the stated expected point or no-intersection behavior; done means the exact-corner case no longer returns the entire box side.