Questions about subnet division and subnet mask odd

As for subnet division, the subnet mask is odd. 1.0.1.0 -- 1.0.3.255 Fujian Telecom converts the subnet mask to an IP segment 1.0.1.0/24--1.0.2.0/23, if two IP addresses are replaced by binary IP addresses in a general way, or the budget is 0001.00000000.00000001.00, the subnet mask may be odd.
1.0.1.0 -- 1.0.3.255 Fujian Telecom converted to 1.0.1.0/24--1.0.2.0/23

The above is an IP segment. after dividing the subnet, we can get the next two CIDR blocks and the subnet mask. if you use the general method,

Change two IP addresses to binary for variance or budget
00000001.00000000.00000001.00000000
00000001.00000000.00000011.11111111

The obtained subnet mask is

11111111.111111.1111111101.00000000
255.255.253.0

However, the third segment obviously does not comply with the continuous and continuous zero rules, but does not know what the basis for dividing the top two network segments is. hope you can answer this question and wait online. thank you!

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Do you want to understand the principle or have specific requirements.
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1.0.1.0 -- 1.0.3.255 is divided by a 24-bit mask (class C website). There are 3 network segments in total.

11111111 11111111 11111111 00000000 mask

00000001 00000000 00000001 00000000 network segment 1
00000001 00000000 00000010 00000000 network segment 2
00000001 00000000 00000011 00000000 network Segment 3

When the mask is 23 bits
11111111 11111111 11111110 00000000 mask
In three network segments and, respectively, get (red part)
00000001 00000000 00000001 00000000 network segment 1
00000001 00000000 00000000 00000000 result 1
00000001 00000000 00000010 00000000 network segment 2
00000001 00000000 00000010 00000000 result 2
00000001 00000000 00000011 00000000 network Segment 3
00000001 00000000 00000010 00000000 result 3

Obviously, result 2 is equal to result 3, so it is a network segment.