Explain to me why the 3 way ML has better odds than the -0.5 goal?

Apologies in advance because this has probably been answered over and over again and I still consider myself an entry level football bettor with only 2-3 years under my belt but what's the rationale behind odds that are similar to this? 

Team A: -0.5 goals (-120)

Team A: 3 way ML: +100

To me, it just doesn't make sense.  "Logically" you would just take the odds that are better. In the event of a tie during regulation for the 3 WAY ML bet, you still lose BOTH bets. Are odds like this an indicator of a game being a tie?

-Rationally, I would think that similar odds to those above would logically be priced at the SAME PRICE.

Team A: -0.5 goals (-120)

Team A: 3 way ML: -120

-If there were ANY deviation, no matter how small, 1/2 points of juice, you would take the one with less juice. 

Team A: -0.5 goals (-120)

Team A: 3 way ML: -118 <<< You'd bet this.. 

------------------------------OR---------------------------

Team A: -0.5 goals (-119) <<< You'd bet this.. 

Team A: 3 way ML: -120 

Thanks in advance.. 

Don’t over think it, you’re correct. Just take the option with the lowest juice. I can’t speak as to why this occurs, but it happens fairly often. Albeit not with the disparity of -120 and +100. You don’t see that super often at the same book. 

Regardless, you are correct. Hope this helped 

Pretty sure it's some algorithm that sets lines on the amount of bets on both. I get that it's the same bet but I see it a lot.

Doesn't the -0.5 allow for an extra time win, while the +100 loses if the win occurs in extra time?

thats all this is 

the betting limits on moneyline compared to goal line often differ therefore one with be juiced differently to draw more money towards one.