Weekly Extreme Competition 432 was found to have two solutions, by Sysudoku coloring.
A hidden unique rectangle appears in line marking close. Then an attempted 132-wing fails because there are too many 2-candidates around. It fails as a 3-BARN because more than one value is restricted to a single unit.
The ALS_19 brings the collapse triggering clue E7.
A near collapse leaves only a cluster revealing two solutions. That must have brought some anxiety back at the Weekly Extreme Competition office.
433, however, was well defined. An early cluster developed into two, one resolved by a bridge wrap, and the second, by an AIC wrap.
Starting with a 4-fill, ending with a naked pair and a cluster.
On the line marked grid, an intended boomer becomes an ANL.
The follow up brings three boxline removals
Then another 1-way turns into an ANL to remove 5r9c9.
Adding a second cluster, the 3-candidates in c4 clash to make bridge (orange or blue).
And when another 1-way to ANL creates boxline SWr8 to remove 6r8c3, . . .
And leave blue and red as opposing colors. Keeping blue and green, red must go.
One more 1-way turned ANL leaves a two candidate boxline for a naked pair to confirm W9 and wrap blue,
for a green orange solution.
Systematic Sudoku 