I'm not hearing an "l" - her "a" sounds strangely flat to me, but you're going to get inconsistencies in any speaker over time. By the same token, it's not really a slender "t" at the beginning, just a not very clear broad "t".
You can compare how she pronounces it in other exercises:
"Tagaimid amach nuair a ólaimid beoir." - https://www.duolingo.com/comment/4326105
"Tagann sé agus tagann sí. Tagann siad." - https://www.duolingo.com/comment/4289006
""Tagann na béir ar ais gach lá." - https://www.duolingo.com/comment/4397338